On the Formation of Sastrugi Across the Western Greenland Ice Sheet

While Thomas has been navigating our trail and repeatedly monitoring the GSSI console to record data, I, Tate, had the luxury of placing my skis in his track, which removes the fuss of steering the snow machine, and pondered the surface features of the snow.

My curiosity of Sastrugi germinated during the NASA snow working group I attended in January. During a lecture by Matthew Sturm he mentioned that their formation remains a mystery. I couldn't contain the thought, studiously raised my hand, then blurted, "Sastrugi form like migratory birds so as to minimize wind friction upon formation."

Sastrugi formations are a powerful treachery for the traversing snow machine. During the first attempt towing the radar sleds north from Raven Camp to Core Site 1, the strong Sastrugi had bent the angled steel FMCW Radar mount like a violin bow, battered the deep-cycle batteries like they were matched up at the MGM Grand for Fight Night, and ironically defeated the surface roughness laser rattling it from its perch into a deadly tumble. The GreenTrACS Team did bound off the ropes, wielding U-bolts and soldering irons in the coming rounds.

 A rare crosscut Sastruga with overhanging tip nosing towards the surface.
(Photo - Erich Osterberg)

During the lackadaisical afternoons of GPR traverses I examined a thousand km of boundless Sastrugi. I attended to the subtle and braided details of the surface. I have contrived a few principles which plausibly identify the origin and growth of the perplexing Sastrugi. May blogspot serve as the game warden to any publication poacher.

An individual Sastruga has a lifespan. There is a conception, a birth, a maturation, changes in its direction, an adulthood, and later yet a burial. It is romantic in a sense, though a jar of Nutella will appear romantic after some amount of time on the ice sheet.

I have only personal record to describe the Sastruga lifespan. But I hope to direct a study testing this hypothesis. Doctors, I may be crazed.

After the first bout with Sastrugi, I became keen to observe the spatial variation of the snow. I took note of the weather conditions, precipitation, wind events, cloud cover, and temperature. As the weeks passed by I gathered my intel and began a survey forecast for traversing the radar equipment. In the evenings after a survey with an eager jeer the team would inquire about the latest developments in my understanding of the vast Sastrugi. So I went on and told 'em.

Before Sastrugi are Sastrugi, there exists a temperature gradient and a gentle breeze to drive faceting of the snow surface. The feather-like facets have the tendency to cluster in the breeze. These clusters are the nucleation sites of the to-be Sastrugi.

When surface wind speed surpasses 10 knots the surficial snow is carried within a density current of near-laminar flow. It’s mesmerizing to watch the braided blowing of snow across the surface of the ice sheet. As a fragment of snow collides with a nucleation site, accretion of snow may occur. A snow fragment is guided left of, right of, above, and/or halted by the bunch of facets. These outcomes are dictated by the lateral and vertical incidence of the snow fragment, and the air pressure about the nucleus as a function of its size and the wind speed.

The continuous stream of flowing snow navigates the clustered facets. A baby Sastruga is born. This formation has a developed, golf-ball-size cluster and elongated, narrow ridge of snow at its tail.

The width of a linear current of blowing snow is between 10 and 30 centimeters, much wider than the forming young Sastruga. This allows for growth of the Sastruga and development of the canonical flying-V form.

With a constant wind velocity the V is broadened and a wind crust becomes pronounced. The many neighboring Sastrugi become enveloped into a larger dune formation. This feature is often braided on its surface, as the laminar flow weaves about the many neighbors.

If the direction of the wind shifts, the lesser compacted tail of the Sastrugi is scoured away creating a mogul formation within the duned Sastrugi. Rare crosscut Sastrugi form a drooping, leaf shaped cap (the tip of which nearly noses on the surface) after the lighter substrate has been scoured away.

Large dunes may form like boomerang of 5 square meters in area and 50-75 centimeters tall; I have not observed many features larger.

Across the Western Greenland Ice Sheet, several inches of snow will precipitate in events weekly to bi-weekly. The Sastrugi are laid to rest. Driving across such snow forms a rolling trail with a wavelength about that of the snow machine. "Fluff Kitten," Forrest calls it.

T'Ocho signing off.

On the Nomenclature of T8: The Birth of a NickName

Early in every trip, nearly immediately, slang names of Tate are created. This follows me however, and where-ever. Perhaps in egocentricity, I receive a particular amount of Nick-Naming. Spud, Tater, TaterSalad, DarthTater, T8. I wonder how the man named Nick reckons with Nick-Naming.

Many of these names I receive often, or always - Tater-Tot. I like all forms of my name in a saying. A particular name re-birthed on this trip. T'Ocho.

Hugo, my Ecuadorian office mate in Boise dashed the Spanish flavor upon the coder spelling T8, after reading the revolving font of my screen saver, "Windows T8". "Ahhh, T-Eight - Like T-Ocho..."

T'Ocho and Forrest share a tender moment. (photo by Erich Osterberg)

On an isolated landmass -- which speaks little Spanish -- I striped my bomber 2-liter Thermos early in the trip with duct-tape so the crew would recognize this is T8's Thermos, as we are all issued the same stainless flask by CPS. T8 is simple to write with duct tape.

I had stepped out of the kitchen tent onto an evening ice sheet. A moment later Thomas called over to me, "T'Ocho, how about we back up some data?" I was stupefied. Humorous to me, how similar people are, and how simply Thomas must have read "T8" on my Thermos, and thought, "T-Eight, like T-Ocho."

Erich spun a derivative off T'Ocho, Calling me The-Ocho. When "The" is presented before a word beginning with a vowel, the long E sound is pronounced. Though Erich would state The with both long and short pronunciations. He would to say Hey'Ocho, similar to the Spanish T'Ocho. Likely stemming from the indiscernible name callings of his Mother yelling for either him or his brother. "Did she say Hey Rick! Or Erich?"

#thisisforthehomies
#daveocho

T'Ocho out.

Some Summit Work - Done

Erich here checking in from Summit. I have to admit that I got a little choked up when we finally arrived at Summit after midnight monday morning. Pushing the "stop" button on the snow machine that last time was a long time coming - all the months/years of planning, the 5 weeks of work here on the ice, and then the 16 hours of snowmobiling on Sunday to actually make it to Summit. What a ride.

Our approach to Summit was not easy - avoiding the clean air sector and the
ICESat line south and west of the station. The diagonal gray line is the Summit Station ice runway.

It turns out that the most difficult part of our whole 1200+ km traverse was the last 10 km approaching Summit. The "clean air" sector for atmospheric measurements at Summit is towards the south (since the winds come from the south most of the time) - unfortunately, we were coming from the south too.  Snowmobiles are not allowed in the clean air sector because they're not clean. So we had to detour well west of the Station, then continue 10 km north of the Station, and eventually approach from the northwest. It was tricky because there is an "ICESat Line" also west of Summit where they validate satellite measurements of Greenland's surface elevation - and we had to avoid that area too. Everything is marked with flags - the challenge came from differentiating the "come this way!" flags from the "stay away!" flags, which were often the same color. It took Summit Camp Manager Kaija talking us in on the satellite phone like an air traffic controller - her watching our headlights from the Big House - before we were able to find our way to the station without compromising someone else's science project. You can see our tortuous path to Summit on the "where we are" breadcrumb tracker page, and in the picture above.

T'Ocho triumphantly hoists his cot after successfully collapsing it - for
the first time since April 29th. 

Today we completed the last of our major tasks here at Summit before Thursday's flight to Kanger. First, we broke down all of our gear and science sleds to sort the gear into piles - stuff going back to Dartmouth, stuff going to Boise, stuff going to Kanger, and stuff staying here. We've become awfully (too) familiar with this gear over past 5 weeks.

Before: Our sleds all loaded after arriving at Summit. Tent city is in the background on the left.

After: T'Ocho dancing on an Air Force pallet after we finished sorting and re-packing the gear.

Thomas completed his last kite survey to get a high-resolution Digital Elevation Model (DEM) of Summit Station. PI Bob Hawley was here last summer and conducted a similar survey with his drone. So Thomas will be able to compare his DEM to Bob's to see how much the glacier surface has changed around camp from drifting around the buildings.

Erich with the famed GISP2 Ice Core borehole.

I also completed our last science snowpit - number 22 of the expedition. It was a very cool experience for me. First, I got to visit the GISP2 ice core borehole, which is kind of like a baseball fan going to Fenway or Wrigley for the first time. GISP2 was one of the most important climate records ever collected - it fundamentally changed the way we understood the climate of the last ice age. My PhD advisor Dr. Paul Andrew Mayewski (UMaine) was the lead PI on that project in the early 90's, and so it was a special experience for this ice core scientist. Then, completing a snowpit here at summit - a place from where so many of my samples have come over the years (including an ice core named after my first born!) - was very satisfying. All in all, my first visit to Summit has been awesome.

The last of 22 snowpits - this time at the top of Greenland.

Tomorrow (wed) we will finish labeling our gear for the shipment home, and tomorrow night we'll give a short presentation to the Summit staff and other scientists about our project, and premier Forrest's video of our expedition. We'll be sure to post the video to the blog here once it's in polished form. Gabe hopes to be back in the air wednesday recovering the caches at the Core 3 and Core 5 sites after being grounded today due to weather. We're looking forward to reuniting with him Thursday night in Kanger.

One last note - posted on the bulletin board here at Summit are two photos of Bob from the FIRST Summit Station winter-over crew in 1997-1998. Bob is in the bottom left of both photos. Legend.

Our very own Bob Hawley (bottom left in both) - a legend here at Summit.

Made it to Summit!!

After a 16 hour day of snowmobiling 400 km from core 7, we finally made it to Summit at about 1 am last night. It was incredibly surreal first seeing something on the horizon besides snow and clouds, a man-made building standing well above the snow as a beacon of hope for some warmth and relaxation. The whole day was spent alternating between using our thumbs and palms on the throttle, standing vs sitting on the machines, listening to books on tape or podcasts, and trying to stay awake as we stared at more snow and sastrugi than one could possibly imagine. Once we got to Summit, we happily clambered into the Big House and ate some delicious leftovers, guzzled a bunch of water (without having to melt that snow first), relaxed in the warm comfortable room, and finally clambered into bed, exhausted, at 3 am.

Before: April 28 (photo - Forrest McCarthy)

After: June 5 (photo - Forrest McCarthy)

After waking up this morning we relaxed in the Summit buildings, ate some fresh fruit and drank real, non-powdered, milk, and enjoyed not having to huddle on a tote box when eating as the wind howls against the tent. Most of the crew showered and put on clean clothes that we had shipped up to Summit from Kanger, nearly 5 weeks ago. The atmosphere inside was quite happy and engaged as we recounted tales to the awestruck staff and scientists at Summit, confused as to who these smelly-beardy-goofballs were that appeared in the middle of the night without a plane. For us, it was quite bizarre to be surrounded by other people (remember that it had just been us 5 for the past 5 weeks straight, with only one flock of  birds and a few overhead planes to break the solitude) who didn't laugh at our inside jokes or suddenly burst into song at the mention of Pitch Perfect. Not only were there other people, but the Big House has couches (so much softer than our snowmobile cushions), laundry machines, internet, electricity, and a small smattering of plants growing in the windowsill.

Tate dismantling the science sled in front of the Summit Big House

Erich happily moving into an Arctic Oven in Tent City, Summit

I volunteered (or was voted off the ice sheet - still not sure) to hop on a small Twin Otter plane to pick up the caches we had left behind at Cores 3, 5 and 7. So only 12 hours after arriving at Summit I was off again to dig out our ice cores and load the empty fuel barrels into the plane. I've never before had a plane filled with only the pilot, co-pilot, and myself, so I felt like a rock-star as we covered that same 400 km in 1.5 hours that had taken us 18 hours the day before. We carefully dug up the ice core boxes and loaded them into the plane - knowing that it was a race against time before they turned into a very expensive puddle on the floor. We miraculously took off with an extra few thousand pounds of gear and headed back to Kangerlussuaq, flying over spectacular melt ponds and crevasses that we had avoided on our snowmobile traverse. I was ecstatic that I saw a few crevasses at the exact locations that my algorithm predicted they would be!

Trying to figure out how all that gear (plus 5 ice core boxes) will fit into that tiny plane

The view from the back of the plane, where I was happily squished for the two hour flight back to Kanger

Upon arriving in Kanger we were met with a team of Polar Field Services staff, who quickly and carefully whisked the ice core boxes into a large freezer (filled with ice core boxes from other scientists around the Greenland Ice Sheet), moved our gear to the warehouse, and started to dry everything that had been covered in snow and ice for the past 5 weeks. I glanced at the 1000 unread emails, 1000 new GroupMe messages, 100 Facebook notifications, few dozen texts, and even a voicemail from my doctor from a month ago before deciding that it could all wait another few days. I then attempted to email Erich and Bob that everything went well when, suddenly, the smell of my own clothes and 5-week-unshowered-body overwhelmed me and I had to put the phone down to jump in the shower. Never before has the feeling of warm water and soap made my skin feel so amazing.

Looking at crevasses from the Twin Otter that we happily avoided during the traverse

My first site of land at the edge of the Greenland Ice Sheet

I'm off to bed here in Kanger even though the rest of the group is still up at Summit for the next three days. It was very bittersweet leaving the group this afternoon even though I'll see them again on Thursday when they fly down here with the rest of the gear. Tomorrow I'll briefly head back up to the ice sheet to pick up the rest of the cached ice cores and fuel drums when the Summit team organizes gear and packs it up to be shipped back to the states.

Sending warm, showered, well-fed greetings from Kangerlussuaq, Greenland

From Erich at core 6- Memorial Day!

Hi folks its Erich here. This has been an amazing expedition for me. Bob, HP and I have been planning this research for over 5 years, and intensely planning this field season for the past 8 months. We're now a week away from finishing the year 1 expedition, and all that planning has really paid off. We're on schedule to complete all of our research objectives - which were pretty ambitious to begin with. I couldn't be happier with how things have gone this year.

We have a storm day here on Memorial Day, so I have some time to share with you some of my thoughts about the expedition so far.

Greetings from Camp Dartmouth!

 
Climate Change Evidence is Everywhere

Our overall research objectives here are to understand how climate change is affecting the balance of snowfall and surface melting on the Greenland ice sheet - and ultimately what that means for future sea-level rise. 2015 SHATTERED the record for highest global average temperature, and 2016 is setting a pace to break that record. During this expedition, it's impossible to miss the impact that climate change is already having here.

We can start in the weeks before we even got on the plane in Scotia, NY. The Greenland science community was buzzing on April 11 as surface temperatures over much of the Greenland ice sheet went above freezing and we had our earliest melt event on record. To put it into context, we wanted to avoid surface melting as much as possible on this trip (bad for radar data, ice coring, and snow camping), which is why we chose to be here in late April and May, into early June. Usually we don't see surface melting at our locations until mid June or later. So to see in EARLY APRIL (!) was stunning.

The culprit was a big loop in the Jet Stream called an Omega Blocking pattern. This brings warm air from the south up to Greenland, but moves cold air down over areas to the east and west of Greenland like to the USA East Coast. These blocking patterns tend to persist for weeks at a time, and it was still in place when we arrived in Kanger on April 25 when it was in the 60's or warmer for that first week. Kanger is usually still feet-deep in snow in late April - but it was snow-free and brown this year (like New Hampshire was all winter!). The rivers draining the ice sheet were flowing much faster than normal, and the local hunters were unable to get to their normal sites because the sea ice was melted too far back.

t-shirt weather in Kangerlussuaq, Greenland...

Meanwhile, it was snowing in Hanover, NH!! Yes, it was 30+ degrees warmer in Greenland than in Hanover in late April. Gabe was wearing shorts and tee-shirts in Kanger while our families back home dealt with a late-season snow storm. The same type of blocking pattern produced the famous melting event in July 2012 that caused surface melting even at Summit, Greenland.

The question is - what causes these blocking patterns? And are they related to climate change?

This is an area of active research and some debate in the climate science community. It's also a particularly important question because it represents the interface between climate change and weather change. Of course, people experience weather changes, so it strongly influences people's perception of climate change. A research group out of Rutgers led by Dr. Jennifer Francis has shown that declining arctic sea ice and snow cover in Siberia (both definitely from climate change) help to contribute to these blocking events. The jet stream responds to temperature gradients from the equator to the pole. As the arctic warms faster than the mid latitudes with climate change (due to things like melting sea ice and decreasing snow cover!), the jet stream tends to slow down, and as it does, you can get more of these big jet stream loops than cause blocking highs. So while I'd personally say that the science on this point is not settled, there is good evidence that these blocking patterns happen more frequently with climate change.

Omega Blocking in Greenland leading to melt events

(SIDE NOTE: The reason why Hurricane Sandy veered west into New Jersey - an EXTREMELY rare course for a hurricane to take - was due to one of these blocking patterns).

In the ice cores we are collecting, we can see that these surface melting events have become more and more common in recent years. The ice that forms when snow melts and then refreezes looks very different than the ice that forms when snow slowly compacts over time without melting. So we can distinctly see summer melt events in the ice cores as we collect them. 2012 stands out as a huge melt year in our observations here - that was a really warm summer in Greenland including the previous July Omega Block melt event. It's a solid meter of refrozen meltwater in the ice cores, and it stands out as a very dark reflector in our radar data. As the cores go deeper and deeper, further back in time, we see fewer and thinner refrozen meltwater layers. This is consistent with our records from Greenland weather stations showing warming temperatures since the 1950s. In a paper we published last year, we showed that if you remove the temperature signal caused by natural climate cycles (including the North Atlantic Oscillation and Atlantic Multidecadal Oscillation), there has been a steady warming in NW Greenland of 2.9oF since 1952. That's about three times the global average warming rate.

It's turned much colder here for the past week, which has been nice for our work. But our custom weather forecast from GreenTrACS project PI Dr. Sean Birkel (at UMaine) shows more possible surface melting on Thursday and Friday. I have a feeling that this summer is going to be like the summer of 2012 - record low sea ice, low snow cover, and frequent melt events in the Arctic. 2015 was such a hugely warm year, all that heat in the atmosphere is not just going away. Stay tuned.

A Science Machine

The night before we flew from Kanger to Raven/Dye-2, Gabe posed the question at dinner: "What are you most looking forward to?" 
My response: "I'm looking forward to 5 days from now when we have things figured out, everything is working, and we're dialed in".

5 days was a little on the optimistic side. It took more like 10 days before I'd say we were fully dialed in - a science machine. In those 10 days we learned:

• How our suite of scientific instruments can best be hauled across the ice sheet to get the best data. This is no small task. The power requirements alone for the 4 independent radar systems are challenging, plus the 7 (yes, that's 7) different GPS's we have running (which doesn't include the handheld Garmin GPSs we use to navigate the snow machines). And then there's the laser. Yes, we're dragging a laser across the ice sheet (cue Dr. Evil). Each instrument 'likes' to collect data at different speeds, at different heights above the ice, at different time intervals, and has different science objectives. We now have a 'science sled' that works well for us almost all the time.

• How to best haul 55-gallon drums of gasoline from site to site. It's hard to do much with a snow machine without gasoline. During the first traverse day we punctured 3 of the 4 drums of gasoline we had at that time! This was a HUGE problem!! They were slow leaks - although we still ended up bathed in gasoline - and a little bubble gum helped to stem the flow until we got new empty drums to transfer the fuel into (thanks for the tip, MacFerrin!).

You can imagine (although, why would you?) that there are dozens of possible ways to cargo-strap a drum of gas to a sled: upright, on its side long ways, cross ways, with various types and amounts of padding in various places, with the straps crossed, or parallel, hooks pointed in, hooks out, etc etc.

We approached the problem like scientists. After transferring the fuel from the punctured drums to new drums, we had some punctured, empty, useless drums to experiment with. So we tried all these different possible strategies and after each new attempt, drove the sled around camp at high speed (thanks Gabe!) to see how much the drum moved and dented. After several hours of this, we found the ideal (we think) solution. So how do you best haul 55 gallon-drums of gasoline across an ice sheet? Starting with a wide siglin sled, put down two tarps (padding), then a sheet of plywood (doesn't slip), then two ridgerest foam sleeping pads, then the drum on its side across the width of the sled on the pads, with two cargo straps crossing the drum diagonally (making an X) to secure it in place. Between the drum and cargo straps are another 2 foam sleeping pads, and then a heavy canvas tarp to prevent the ratchet on the straps from rubbing through the pads down the drum (which would puncture the drum). The cargo strap hooks need to be looped through the sled tie-downs and hooked back on themselves, or hooked to a metal caribiner (so they don't rub through and break the tie-downs), with all hooks facing away from the drum (again, that puncture thing). And voila - you have a safe and reliable way to move fuel around the ice sheet. Just in case you were wondering.

The ideal drum tie-down

• We also learned in these 10 days what our schedule would be at each camp/science site. It's important to develop a rhythm of day-to-day life so that everyone knows what is expected of them and what is possible in these conditions. How far can we really go on a radar 'spur' to the east or west in a day? How long does it take us to drill a 30 m ice core? How long does it take to setup and breakdown camp? (more on that below). So our ideal schedule is:

Day 1: Camp move
Day 2: Drill ice core and radar spur to the west
Day 3: Cache run to next site, and radar spur to the east, and camp radar survey.
Day 4: Camp move
This ideal schedule only worked out once - at Site 3. Throw in storm days when we can't work, equipment malfunctions, etc, and we usually add another 1-2 days to each site. But we found our rhythm and that's what's most important.

• Related to the schedule was learning what everyoneís roles would be - not just for the science, but for the day-to-day camp activities as well. Who would take responsibility for each instrument? Who would backup data each night? Who is a good cook (Thomas)? Who's not (no need to shame here)? Who's good at building the bathroom (Forrest)? Who has the best skills with small electronic devices (Gabe)? This was all part of becoming a well-oiled science machine.

Chef Thomas with MegaSoup2.0

A Typical Camp Move Day

Our moves from one camp to the next are some of our longest and most challenging days. Here's what they are like:
7ish: Wake up. Start packing up personal gear in tent. Turn on generator to top up science instrument batteries.
7:30: Daily check in with our CPS logistics team in Kangerlussuaq
8:00: All personal gear packed and personal tents empty. Breakfast.
9:00: Gabe, Forrest and Erich start breaking down personal tents and building sleds. Thomas and Tate prepare the radars and science sleds for the day's data collection between campsites.
10:30ish: Start breaking down the kitchen and science tents and continue building sleds.
Noonish: Tate and Thomas start slowly (~10 kph) traversing to the next camp, collecting data the whole way. Erich, Forrest and Gabe continue building sleds and finishing camp breakdown. Break down the bathroom tent.
1:30ish: Gabe, Forrest and Erich are done - have some lunch.
2ish: Erich, Gabe and Forrest start traversing to next camp at ~25 kph.
3ish: Forrest, Gabe and Erich pass Thomas and Tate on the 'road' and check in with them.
5:00ish: Forest, Gabe and Erich arrive at new camp. Start by padding down the tent platforms by driving back and forth with loaded sleds in an east-west orientation. The strongest winds come from the south, so we orient camp in a roughly east-west line to prevent one tent from causing snowdrifts on another.
5:15: Setup kitchen Arctic Oven tent. We can have this fully setup, with everything back to its place inside, in about 30 minutes.
5:45: Setup science Arctic Oven tent. Again, everything back in its place in 30 minutes.
6:15: Erich and Gabe setup the 4 personal tents (Forrest prefers to sleep in the Pod so no personal tent). Forrest sets up the bathroom tent. Each personal tent takes about 10 minutes to put up and fully stake out. We've now setup and broken down these Mountain Hardwear Trango3 tents 44 times. We're getting good at it.
7:00: Erich and Gabe setup cots and personal gear in each tent, dig out boot bays at the entrances, and berm the personal tents with snow. Tate and Thomas check in via sat phone and give their ETA - usually around 9 pm. Forrest starts making dinner.
8:00: Gabe, Erich and Forrest gather in the kitchen tent and start eating dinner.
9:00: Thomas and Tate arrive - usually very cold. Snow machines are fueled and oiled, science instruments turned off, generator turned on to recharge batteries, and they eat dinner.
10:00: Data backup and eventually collapse in bed.

Camp all set up

What is amazing is how each camp feels the same. Everything is in roughly the same place at each site, and in the same place inside each tent. And the scenery doesn't change (flat & white). So itís like groundhog day. It must be particularly odd for Thomas and Tate to leave one camp, drive all day, and then seemingly arrive at the same camp that night.

Tate with the science sled on a late arrival...

A Frozen Ocean

It's amazing to me how snowmobiling across an ice sheet feels so similar to power boating across the open ocean. I did my Master's degree research in New Zealand out on a research vessel studying underwater canyons far at sea - so I have some experience doing both now.

It's flat as far as you can see in every direction, just like being out at sea. The winds makes sastrugi - waves of snow - that feel just like waves on the sea. There are rough days and smooth days, related to wind strength and direction. Whereas ocean waves form in minutes to hours and move in seconds, sastrugi form in hours to days and move just as slowly. The sound and smell of the snowmobile engines even evoke memories from New Zealand for me. In both situations, you are utterly out of place as a human. Get rid of the boat or snow machine and tents, and you are not long for the world. In both, you occasionally see some wildlife. The other day we had a seagull fly overhead and the analogy was complete. Of course, the similarities make sense: they are both just water in either solid or liquid form.

Forrest and Gabe holding the moon...

A Note About Food: and Pop Tarts (arguably also a food)

Central to every glacier expedition is the food. I learned long ago never to let undergrad or grad students plan and buy the food without close supervision (have you ever looked into a grad student's, or worse - undergrad student's - refrigerator? Don't). So I have taken on the role of food planning and purchasing for most of my recent expeditions, including this one.

The food needs change for every expedition. In Denali, we have to haul much of the food on our backs, so weight is a strong consideration. And in Denali, the lengths of our expeditions are difficult to predict due to weather, so it's hard to correctly plan food quantities. Here, we are hauling around 6,000 pounds of equipment by snow machine, so weight is NOT a concern. And we knew when our flights to and from Greenland were - we HAVE to make those flights - so we knew our duration.

So for my expedition food planning, I've developed a very detailed spreadsheet with every food item and the amount one needs per person-day, taking into consideration personal preference of group members. For example, we have 4 coffee connoisseurs on this expedition, and somehow need 4 separate coffee pots - I suppose just in case three of them break (can you tell that I'm not one of the 4?). As another example, some people like canned fish, others really don't. You get the idea.

We have 200 person-days on this expedition, and so I planned on about 275 person-days of food to allow us some flexibility of choice (again, since weight wasn't an issue). That comes to about $3,000 worth of food, which took three separate shopping trips to BJs, Hannafords and the Hanover COOP (in declining order of cost) to procure. So we are NOT going to run out of food. Although we ARE going to run out of CERTAIN foods.

Pop tarts come to mind.

The way I make the food shopping list is a few weeks before the trip, we have a conference call with everyone and we go down the list line by line: "OK breakfast. How many meals per week will each person want cereal (and which kind?)? Oatmeal? Cream of wheat? Granola? Pop tarts?..."

And here is the thing: if people don't speak up, then I can't do my job properly. Every year, with every expedition, the typical response on this phone call is: "I'm easy - I'll eat anything."

This is both incredibly unhelpful and a bold-faced lie. I understand that people are just trying to be accommodating, but it makes food planning very difficult.

The truth is even if someone WILL eat anything, everyone WANTS to eat some things more than others - i.e., we all have preferences. So if you have a group of 'easy' people, what inevitably happens is that everyone chooses their preferred food first, that food disappears, and everyone is stuck eating food they will tolerate but not really like.

This is the situation I'm always trying to avoid. Food is central to both good health and good morale. Anyone can eat anything for a few days or a week. But we're here for 6 weeks - we need good food to stay healthy and happy. I learned a lot about this from my friend, ice core drilling extraordinaire, field food gourmand, and arctic field expert Mike Wasczkiewicz.

So back to the Pop Tarts. When we got to Pop Tarts on the list during the phone call, the response was luke-warm at best. "Sure, I'll have one every now and then" seemed to be the common response. So I bought 50 person-meals of pop tarts, or 10 person-meals each, or one breakfast every 4 days per person. That comes to 100 packs of pop tarts with 2 per pack (so 4 individual tarts per person-breakfast).

Turns out that we are all closet pop tart addicts.

What happened was all-too predictable. As the pop tart supply started to dwindle, there was a rush on the remaining stock. There was some hoarding (I suspect), some hiding (I did bury a pack of 24 deep in the breakfast box - but only for the good of the whole team. I didn't tap into it.  I swear), and a lot of nervous mornings. Shifting eyes as our minds swirled with accusations: "Is he having ANOTHER pop tart? Didn't he have one yesterday? Wait, is he having one for LUNCH?!?!" And so on.

So what happened? How did this go so wrong with such a simple, delicious, food-like product?

My guess is that the problem comes down to a difference between what one eats in 'the field', and what one eats at home. I don't think I've ever eaten a pop tart at home. Honestly. But here, I can't get enough of them. And here's the odd thing - it's not like I'll eat them at home when I get back in a couple weeks. I will go back to never eating pop tarts - except in 'the field'. This is a phenomenon that my wife has noticed over the years. She'll hear about my trips, and our meals on those trips, and note: "you never eat that at home!"  I realize now that this is not unique to me.

So what is one to do? I think I need a multiplier for each item on my list to account for the field-food effect. Some foods will have a multiplier of <1. For example, Honey is a real pain-in-the-rear to deal with on a glacier because it doesn't flow. So maybe Honey has a multiplier of 0.25, meaning that one has 1/4 as much honey on a glacier as at home. (I note that we have not actually opened up a single honey jar yet - and we're on person-day 150. So maybe the multiplier should be 0.1). Peanut butter is similar - it's really hard to spread frozen peanut better; give it a multiplier of 0.4.  Other foods will have a multiplier >1, like pop tarts: maybe a multiplier of 2 or 2.5. That would be about right for this group.

Other things can also go wrong with the food. For example, we've managed to lose one of our two 5-lb bags of pancake mix. I usually cook pancakes and bacon for the group on storm-day mornings. It keeps morale up, and pancakes take a while, and we have time to kill on storm days. But not this morning. No more pancakes. I KNOW I bought 2 packs of mix. It's on the list, and I remember seeing two. But one has disappeared. Maybe someone is using it as a pillow? Maybe it got left and buried in the snow when we re-organized food boxes at Camp 2? Or maybe it's out there in a food box somewhere, and we just can't find it under all that peanut butter and honey. Who knows? But it was plain old granola for breakfast this morning. Such is the hard life on the glacier.

Bacon-wrapped sausages: An Ice-sheet Memorial Day special!

From Gabe at Core 6

All rigged and Snowmobiling For Science! Photo: Forrest McCarthy

I’m writing to you from the inside of my (somewhat odorous) tent at Core 6, nearly 400 km from our starting location at Raven/Dye 2. We’ve now drilled six of the seven proposed ice cores, collected a thousand miles of radar data, broken and fixed nearly everything that has an on/off switch and, unfortunately, eaten every single PopTart on the Greenland Ice Sheet. Although the weather has been a bit chilly this week with arctic air blowing from the north (morning temps around -14 F and daytime temps around 0 F), we’ve entered a new weather pattern and “warm” air is now blowing in from the south at 20-30 mph, so today we’re stuck in our tents reading, blogging, and Erich is watching “Pitch Perfect” for the fifth time this week. I wish I was joking.

Measuring Albedo with the spectrometer. Photo: Forrest McCarthy

During our camp move from Core 5 to Core 6 we set up a GoPro time-lapse as we deconstructed four personal tents, the kitchen and science tents, and the poop tent, packed up large sleds with all our gear, ratcheted down several 55 gallon fuel drums so that they won’t puncture, and padded our ice cores to move to the next cache. When we got to Core 6 we set it all up again, but we’re definitely getting faster as we can now erect everything in about 2 hours from arrival. We’ll eventually post this time lapse, but the connection says it would take 322 days to upload at the current connection speed.

Drilling at core 6. Photo: Forrest McCarthy

As Erich and I were drilling the ice core yesterday (we reached 28 meters before running out of non-broken aluminum extensions) we noticed that we’re directly under the commercial flight path from Europe to America, so if you find yourself crossing the Atlantic in the next week be sure to look down for several large yellow tents and a few gray tarps. We’re the only thing that isn’t snow a several hundred mile radius. Maybe we’ll even spell out the name of our favorite political candidate with snowmobile tracks!

Erich, geared up and ready to head out. Photo: Forrest McCarthy

We have four 2-stroke Polaris and one 4-stroke Skandic snowmobiles since we were told the 2-strokes are much easier to fix if something breaks out here. During our calculations and extensive research, we figured that the 2-strokes would get around 8 miles per gallon while hauling sleds and that they require an oil-to-gas ratio of 50:1. So we brought 17 gallons of snowmobile oil and cached 17 fuel drums along the route at a few strategic locations. What we failed to consider was that while surveying and towing heavy sleds, the snowmobiles use an oil-to-gas ratio of closer to 30:1, meaning that we have enough oil to get us to Core 7 and to within 100 miles of Summit, just shy of our final destination. We unsuccessfully searched the snowmobile manual for a way to premix the oil and gas before refueling, to lower the automatic oil injection rate, and even to use an oil substitute (we have lots of olive oil and bacon grease). We asked the snowmobile mechanics in Kangerlussuaq for help and even a few family members to do some research online for us, all to no avail. We have enough oil to get us 300 km, but it’s 400 km to Summit. What we really need is another miracle of Hanukkah. Unfortunately the National Science Foundation doesn’t believe in miracles and doesn’t want us to freeze to death so close to Summit (it would be bad publicity on their Annual Report), so they offered to air drop several gallons of oil at Core 7. Maybe they’ll even offer to bring pizza and beer when they come?

You get stiff after a long science drive... Photo: Forrest McCarthy

During the long spell of nice weather we’ve been working hard to collect as much data as possible and stay on track before the plane leaves from Summit on June 9 – with or without us. I managed to fix the laser during a storm day last week and it appears to still be working after driving it at pretty high speeds over large sastrugi. At the moment the GSSI, Flat Earth, FMCW, and multi-offset radars, various GPS receivers, laser, borehole thermometer, and albedo device are all working flawlessly, though I’m sure something will freeze or break in this windstorm. Two weeks ago Thomas and Tate cooked me a delicious birthday cake using pancake batter and cream of wheat with a scrumptious cheesecake frosting (the text reads “Love Green Tracs”). It was definitely the coldest birthday I’ve ever had but also one of the most exciting. 

Happy Birthday Gabe! Photo: Forrest McCarthy

We’ve had breakfast for dinner nights, made Hawaiian pizza with sugary pineapple chunks, pepperoni, and a pancake crust, we’ve perfected mixing Annie’s Mac & Cheese with Darn Good Chile, and even worked halfway through the 3 lb. bag of Sour Patch Kids. Everyone is quite looking forward to some non-dehydrated vegetables and being able to drink water without having to melt a bucket of snow first when we get back to Kangerlussuaq in just over a week. We definitely have enough food for the remaining journey to Summit, and now that we have all the oil we will need maybe I can convince Erich to let us finally snowmobile joust with some bamboo stakes or pieces of ice core. Until then we’ll keep completing our research objectives and driving north – towards Summit.

Tate, in full gear. Photo: Forrest McCarthy

Flying the Kite-Cam. Photo: Forrest McCarthy

Aerial view of camp from the Kite-Cam

Quick updates from the field- text message at a time!

It seems the gang has been too busy to send me any pictures or extended text for the last few days, but I do get some status updates.  Here are some highlights from them!

From Erich:

"Update. Mon we camp moved to core 5. Tate and the surveyed w everything the whole way. Tues gabe and I drilled core 5 to 27.07m depth.Cold windy miserable day"

The team still got a lot done- with spiral radar surveys and using the kite-camera to survey for surface roughness.

 "Today (wed) was really crappy weather. Gabe & I did pit in the morning before it was too bad. No radar survey today but Tate & Thomas did pit reflector tests with Tate's radars"

The 'pit reflector tests' to which Erich refers are essentially ground-truthing tests- putting a metal reflector at a known depth in a pit and surveying with the radar to determine the radar wave velocity.   It looks like more bad weather will be arriving Thursday, so the team will try to go east if they can.

"Hope to move to core 6 camp on sat. Still planning on all 7 sites and summit. CPS said today that twin otter will leave a case of oil @ core 7 so that should solve the oil crisis."

The 'oil crisis' to which Erich refers is the fact that the 2-stroke oil-injection system has been injecting more oil into the engines than was budgeted- standard 2-stroke mix is 50 parts gasoline to 1 part oil, but the snowmachines themselves do the mixing and have been using more like 35:1 instead.  So the 2-stroke oil brought by the team will run out before they reach summit.  This is just as bad as running out of fuel, as without oil the engines will seize up and stop running entirely...

We're all hopeful that this resupply of oil goes smoothly, and that the weather improves!

Getting into production mode

We’re all finally starting to get in our rhythms up here, which took a bit longer than expected but everyone’s happy to have most of our logistics figured out. We moved 60 km north to Core 2 last Tuesday after the storm cleared and successfully drilled a 30 meter ice core (Erich’s personal record!), collected both east and west radar spurs, measured albedo at various locations near camp, flew a kite to get spectacular GoPro footage of the coring process (internet is too slow to upload videos, but we’ll post them once back to civilization) and aerial photographs to measure surface roughness. After a few different camp moves we’re getting quite speedy at packing up all the tents, science equipment, ice cores (making sure they’re packed so that they won’t break or melt during transport), and personal gear into sleds to tow behind the snow mobiles. The ratchet straps often freeze or get jammed with snow/ice, which makes tying everything down a more exciting challenge.

There's never a shortage of snow to dig on the ice sheet!

We’ve all been listening to music and books on tape while driving the snowmobiles. I just finished listening to The Martian, which was oddly fitting due to our shared experience. Both in the book and on the Greenland Ice Sheet one has to put on special boots, gloves, facemasks, and jackets to go outside, there is no water on the surface, the atmosphere is deathly cold, and any hope of rescue is far far away. Listening to the book made me appreciate having the others here with me and being able to leave after 5 weeks, not 5 years.

On Sunday we moved another 37 km north to Core 3 and began the practice of setting up camp all over again, we’re getting quite good at it now. Erich and I often race each other to put up personal tents and the latrine has turned into a multi-tiered palace: protected from the wind, with a view off into the distance, and even a shovel to hang your jacket on. It’s quite an enjoyable experience if you forget about the subzero temperatures. The coffee supply is slowly starting to dwindle, but fear not, we still have four coffee presses and over 20 lbs. of ground beans, so we should be able to stay caffeinated for the foreseeable future. Although we had cached fuel, propane, and empty ice core boxes here, we don’t reach our first food cache until Core 5, still a week or two away. Good thing I was deliriously tired when packing the cached food boxes and have no recollection of what I put in there (hopefully lots of chocolate and beer?).

Thomas, surrounded by coffee paraphernalia!  I count no fewer than 6 individual coffee-related items here- can you?

Low sun on the ice sheet from the tent.

Erich and I drilled a 28 m ice core during a very long day today, so we can pack up all that equipment and drive it forward to the next campsite. All day long the wind was howling and blowing snow on us, which the sunshine then began to melt, and everything was covered in a thin layer of ice when the water refroze in the shade. We built wind blocks out of tarps and coolers to protect the ice coring pit, but the spindrift ended up getting into every imperceptible small space (and down your shirt) no matter how many layers you wear. The wind is supposed to die down over the next few days so we’re hoping to get lots more data before the next storm rolls in. Since the storm last weekend temperatures have been extremely warm (mid 20’s during the day and above 0 F at night, which may not seem “warm” to you but remember that we’re standing on top of 8000 ft. of ice and above the Arctic Circle) so we don’t have to wear our giant parkas most of the time and can actually tie knots and tighten bolts with our bare hands, it really makes things easier.

All of the radar equipment is working flawlessly (though it still demands that we drive no faster than 6 mph to collect good data) but we haven’t gotten around to fixing the downward mounted laser yet, maybe we’ll look into that during the next storm.  For now we’re just trying to get as much done as possible and enjoy the great weather and fun company. That’s all for now,

The GreenTrACS Team

Fully loaded, traversing the flat white.