The Pirates of Glacier Mass Balance

By Jon Doty

Mass balance is in many ways piratical by nature. There is a reason why a JIRPer often stumbles across pirate flags with the words "Mass Balance 2012" scrawled onto the walls of camp. We have our map, shovels to dig for treasure, and X marks the spot. However, our modern day plundering involves a somewhat different set of tools, and an altogether different goal. In lieu of a pirate ship, we ride our skis into the horizon, following a GPS in search of science. 

The mass-balance crew on the morning before skiing to the Demorest Glacier pit. Photo by Mary Gianotti.

Although I have lost touch with the outside world, I am told that the day we left C-10 was July the 26th, bound for C-9, tasked with digging mass-balance pits on the Matthes and Demorest glaciers. For all you glacial neophytes out there mass balance is the bread and butter of JIRP science. By digging a pit into the winter snowfall and comparing to the summer ablation (mass lost through melt, sublimation, calving, etc.) we can determine whether the glacier has gained or lost mass over the year, and learn about the variability of the glacier on an annual basis. JIRP holds one of the longest records of glacial mass balance data - having measured Taku Glacier mass balance every year since 1946.  Storglacieren in Sweden is the only glacier with a similarly long data set.

Our itinerary was a nine-mile ski to C-9, pausing to dig a pit just short of camp on the Matthes Glacier. We would spend the night in camp, and then ski down onto the upper Demorest Glacier to dig another test pit before returning to C-9 for the night. On our final day we were bound for C-18 and the wonders of the Vaughn Lewis Icefall and Gilkey Trench.

We waved our final goodbyes to C-10, made a final pit-stop into Dreamland, and then took off down the ski hill onto the vast expanses of the Taku. We skied up-glacier on snowmobile tracks laid down by Scott McGee and the survey team, taking a few short snack breaks along the way, eventually hanging a right up the Matthes Glacier towards C-9. The turn onto the Matthes meant that we were officially on ground that none of us – save for our friendly field staff members Annie Boucher and Matt Pickart – had ever tread upon before - uncharted territory. As we set a course for discovery, I couldn’t help but smile. The interface between the Taku and the Matthes is quite noticeable; as the Matthes spills out into the Taku the flow rates vary greatly, producing a crevasse ridden terrain. These are mostly ankle-biters and nothing to really worry about, mostly affecting scientific curiosity instead of trepidation or thoughts of roping up.

Mary Giannotti and Jon Doty relaxing while Matt Pickart and Chrissy McCabe dig. Photo by Annie Cantrell.

After about four or five hours of skiing through marginal weather, we reached the pit location, and began digging. We dig our mass balance pits in four steps, each reaching progressively deeper down through the snowpack.  The north facing wall is a clean wall, where we make measurements of density, and is never stepped upon as it would affect the snow density below.

At first everyone is at work shoveling out the initial meter of depth, but once the first step becomes defined, only one person can safely fit on each step. At that point, those inside of the pit begin to shovel from their step onto step one, from where it is a shorter shovel throw to remove the snow from the pit. Those who are not within the mass-balance pit take a break and refuel for their next shift inside, or tend the rim of the pit to prevent snow buildup. This year our pits have averaged 3.5 to 4 meters deep, which takes about 4 hours to dig – in the past, however, pits have ranged up to 8 meters in depth, requiring feats of strength that even the Dread Pirate Roberts would shy away from.

The treasure at the bottom of the pit? The annual layer. This line marks the boundary between this year and last year’s snowfall. It can be represented by a variety of features within the snowpack: an undulating ice layer - evidence of suncups from the previous year; a dirty layer – dust and debris upon the snowpack deposited throughout the summer and buried during the accumulation season; or depth hoar – large unconsolidated sugary snow crystals which sits upon the far more dense firn (year-old snow). Once we have found the annual layer we begin to take our data from the pit. We prep the wall of step four (the deepest) into a clean vertical face, and sample the snow at 10 cm (~4”) intervals using a coring device of known volume. Measuring the mass of these snow samples (and the thickness of all ice lenses that cut across our sampling section) gives us a density profile of the snowpack. With this knowledge, we can determine the water equivalent of the accumulated snow at this location on the glacier.  By digging pits at varying elevations and distances along the central profile of the glacier, we can estimate the total accumulation received by the glacier for the past year.

Our pit on the Matthes ended up being 4 meters deep. The depth of our pits creates an interesting logistical problem: how to sample snow cores and ice lenses at fifteen plus feet off the ground. We JIRPers take this as an opportunity to cross the disciplines of science and mountaineering, and so we build a snow anchor and collect data on rappel. In this metaphorical crow’s nest (I know, this likeness is a bit of a stretch) we have a bird’s eye view of the pit we have dug, and can sample the layers safely and precisely.

View of Camp 9, with Matthes Glacier in the background.  Photo by Annie Cantrell

Hungry from a full day’s work, we chugged on up the hill to C-9 through a whiteout, gaining the first views of our home for the next few days only once we were within thirty feet. We all piled inside, leaving our backpacks covered up outside on the nunatak as there was no room indoors for anything more than people. C-9 consists of a single two story building with exactly enough space for about two fewer people than we had in our crew. We managed to squeeze in, and bided our time reading graffiti on the wall and cracking jokes while we waited for the pasta water to boil. After dinner there was only one option: bed.

Interior of Camp 9 with Matt Pickart.  Photo by Annie Cantrell.

Dawn broke with a cloudless sky, and an absolutely beautiful view. After finishing off leftovers from last night we were treated to fresh oatmeal! Our ski down to the pit on the Demorest Glacier was an absolute treat – views of Devil's Paw, the Dipyramid, the Citadel, hanging glaciers, bergshrunds, and so much more. The first half of the ski was a long downhill, and so I sat back and paid zero attention to the track ahead of me as I soaked in the alpine panorama. Once we hit the Demorest Glacier we skied a few more miles of flats to reach the test pit. The sun was hot and bright, and so we blasted some music and got to work. The day was pleasant and the pit went quickly, and as manpower became less necessary within the pit we dug couches into the snow, and laid our socks on our ski poles to dry. Our pit ended up 4.5 meters deep, and so we cored it, and set sail back to C-9, treated to an absolutely incredible sunset just as we topped the camp ridge. Our rations for the night consisted of spaghetti with a mixture of tomato sauce, leftover broccoli cheddar soup, and roast beef for toppings. As we tucked in to bed, strong winds buffeted our home, but thoughts of the coming day’s traverse to C-18 and adding new points to my life’s map lulled me to sleep.

Matt Pickart, Lindsey Nicholson and Jon Doty watching the sunset with Devil’s Paw in the background. Photo by Salvador G. Candella.

The Traverse to Camp 18

By Adam Toolanen

The summer’s third big traverse is the ski from Camp 10 to Camp 18. As a former JIRPer returning as staff member, I have knowledge of the magnificence of Camp 18, which is what kept me going during the 18 mile ski from Camp 10, whereas the students only had my description of the splendor of Camp 18 to ponder as we skied. The excitement of seeing the vast icy expanse on a gorgeous summer day made the journey as rewarding as the destination.

Uwe Hofmann skiing down the hill at Camp 10 for an early morning departure. Photo by Sarah Bouckoms

In the days leading up to the traverse, it was unfortunate that we could not see the Taku Towers - the iconic landmarks of Camp 10. Luckily, the weather cleared on the day that our group left for Camp 18. The first few hundred feet of the 18 mile day consisted of a steep downhill pitch covered in suncups, which always takes awhile to navigate.  Just as we thought we would have a smooth start to the day a ski binding broke on that first, steep slope. Not wanting to have everyone wait at the bottom of the hill, I sent the group on their way and headed back to Camp 10 with Will Jenkins and his broken binding. Luckily, the binding was fixed quickly and we skied back down the hill. I remember being a student on JIRP and never wanting to be behind the group. No different than I, Will cruised ahead of me and soon we caught up with the others.

The trail party takes a snack break, changes some layers and rests for a minute before hitting the trail again. Photo by Sarah Bouckoms

As we traveled up the Taku Glacier towards the Matthes Glacier, we took many breaks to adjust our gear. It is not always obvious how to dress for travel on the glacier. The effect of the sun heating your body is amplified by the solar radiation that reflects off the glacier. Naturally, skiing with a big backpack keeps you toasty as well. On the other hand, there is the massive body of snow under your feet and the cold katabatic winds that cool you off as you ski. Katabatic winds are created by cold air flowing from high to low elevations on the glacier, and can really chill you on a hot summer’s day. Depending on the combination and prevalence of these factors, people have to change clothes constantly. The other challenges are hotspots and blisters. As potentially day-ruining afflictions, these need to be addressed immediately. During the breaks to bandage foot sores and adjust outfits, we also snack to keep our energy levels up and joke together as we rest our feet for a little while.

Author Adam Toolanen on a sunny day on the Icefield. Photo by Jeff Kavanaugh

When I was a student I skied the traverse in a whiteout, so I couldn’t see anything other than the ski tracks from the person in front of me. The staff member leading my group told us about the views of Devil's Paw and the Storm Range, but we could only imagine them. Coming up the trail to Camp 18 this year we were all captivated by the stunning ridgelines and mountain glaciers set against the backdrop of the blue, blue sky and did not have to rely on our imaginations.

The group slowly rising over the final crest of the Matthes Glacier headed towards Camp 18. Photo by Sarah Bouckoms.

As with many things in Alaska, the size and scale of icefield features is deceiving. Setting small personal goals is both rewarding and challenging on such a long ski trip. Promising yourself that you will eat that chocolate bar once you crest the next hill can mean waiting an hour instead of the 20 minutes you were planning on. However, when you finally stand on that hill enjoying your chocolate bar and take in the views offered by the massive slope you just conquered, you can be all the more content with reaching your goal. Some of the students started inquiring about the location of Camp 18 and although I can point out the peaks surrounding the camp, it really takes the whole day for the scale of the journey to really dawn on them.

A group of four carries on in good spirits on Matthes Glacier. Mt. Moore - with Camp 8 on the ridge of rock pointing down towards the first skier - is in the background.  Photo by Sarah Bouckoms

As the group crested the last hill of the Matthes Glacier, we could finally see down into the basin alongside the daunting ridge of the Storm Range. Huge black rock faces towered above us as we pushed through the remaining two miles to camp. The sun was setting behind this ridge and the soft snow froze over, creating a fast and slick surface for our skis. As we neared our destination, the Camp 18 buildings glimmered in the last sunlight, perched high on the nunatak. The final push to Camp 18 offered a view of the mighty Vaughan Lewis Icefall. The top of the icefall billows down a ridge where it breaks up into large crevasses. These crevasses stretch, become bigger, deform and transform into even larger crevasses. When these start to collapse due to the steep slope they are passing over, the icefall really shows that it is in slow, albeit chaotic motion. As my group crested the hill and we started the final downhill glide into Camp 18, the grandiose Gilkey Trench opened up before us. Only as we skied the final quarter-mile to camp did we really see the backdrop which is the surroundings of Camp 18. After 11 hours skiing uphill on the glaciers leading to Camp 18, the group made it just in time for a sunset over the Gilkey Trench. Being back at this magnificent Camp after a long day of skiing is just the reward I was hoping for.

The scale of the Icefield is shown with two skiers dwarfed by their surroundings as they ski up Matthes Glacier. Photo by Sarah Bouckoms

The real treat for me as a staff member was to be able to lead first-time JIRPers on this trip, to one of the most beautiful spots I have ever been to. The students were excited and positive all day, but what they saw upon arrival exceeded all of their expectations. Even I who knew what was in store was in wonder at the realization that this place is still here, that it is real, not just some past dream. I felt like the mediator or the guide who took the students to this place and when we arrived I could just sit back and smile as I watched them explore their new home, giddy with excitement.

After a long day of skiing from Camp 10 to Camp 18, the sun sets on the glaciers and peaks of the Gilkey Trench.  Photo by Sarah Bouckoms.