Glacier Phenology

skiing uphill

In the past, I’ve associated the concept of phenology with flowers and trees undergoing seasonal transformations from buds to blooms. However, conducting research on the Easton Glacier the past several months for my Masters thesis has shown me the remarkably striking ways at which mountain-scapes, too, change with the seasons. These are the abiotic parts of nature that we typically think of only being subject to change over centuries and millennia, not days and months…so much for a “glacial pace.”

Here, I write about the phenology of the Easton Glacier through the Spring and Summer of 2018.

Early May

It is early May and the birds are chirping dawn choruses and the winter rain has diminished. The disparity between the snowy alpine and the verdant lowlands is increasingly stark. Stubborn patches of snow still make the trailhead’s rugged forest road impassable and when we arrive, the snowmobile crew has finagled a winch system to pull their burly trucks and sled trailers across. We giggle at their innovation as we attach skins to our skis, complete a most unusual gear check (duct tape? steam drill? PVC pipes? avalanche gear? snacks?), and finish our coffee.

A team of 8, all members of the Northwest Cruisers Snowmobile Club, has united to help us transport our heavy, bulky research gear up the Easton Glacier and nearly to the summit of Mount Baker. In less than 20 minutes our crew has zoomed from 3,000 feet to 8,500, across cobble-filled creeks and dormant underbrush and unconsolidated glacial till and deep crevasses, all obscured by meters of snow. The undulations of the topography are softened by the snow-laden landscape and the terminus of the glacier is indistinguishable so early in the season.

Niki and I follow a pre-set GPS track to find our first site. Our goal for the day is to use a steam drill (not to be mistaken for a sasquatch-sized espresso-maker) to drill five stakes into the snow and ice, which we’ll revisit through the summer and fall to measure changes in the surface elevation. We probe each survey site to ensure we don’t inadvertently install a stake into a crevasse, and to approximate the depth of the snowpack. When we’re finished, we enjoy the payoff: a ski through thousands of feet of soft spring corn to sites 4, 3, 2, and 1, where we repeat the installation process.

Mid June

By mid-June, the snow bridge across the Easton Glacier’s outlet creek has melted and the high albedo of the cobbles has revealed interwoven stream channels and vegetation. The glacier is no longer accessible via snowmobile and so we approach the ice with an awkward tango of skiing, skinning, hiking, and bush-whacking. We’re wearing shorts and we are disoriented because the glacier’s foreground has morphed into a mosaic of snow, dirt patches, and moving water. ‚ÄúDidn’t we ski right over that waterfall just a month ago?‚Äù

We arrive at the first stake and measure 127 centimeters worth of snow-melt since its installation a month ago. There’s a spider perched on the stake, totally unaware of the climatic changes unraveling around it. We continue up the center of the glacier, moving more delicately and swiftly in certain, seemingly thin places. Sometimes we straddle deep crevasses and peer down into the frozen abysses. Like stratigraphic columns that reveal a chronology of shorelines, the cracks expose layers of snow, firn, and ice from seasons passed.

It’s 3 pm and we’ve made it to stake 3. The snow appears to have gone through a melt-freeze cycle recently and the corn tempts my skiing instincts. On a whim, we decide to pause our research efforts and jaunt up toward the summit of Mount Baker. After all, it might be our last chance to ski volcano corduroy. Around 6:30 pm, we strip our skins and fly down the glacier, at the mercy of gravity and with the current of a disappearing frozen river.

Late July

It’s late July and now we’re wearing hiking boots. There’s a heat-wave in the valley, the trailhead is packed with day-hikers, and we’ve replaced ski poles with crampons and avalanche gear with glacier ropes. The goals of our visit are varied, but first on our list is to install a second stream gauge and measure the creek’s velocity. What’s the diurnal variation (i.e. How much does the streamflow change as the day warms? Can we attribute its velocity changes to snow-melt and/or glacial-melt?)?

After an afternoon of drilling holes into rocks (to install our ‚Äúlevel-logger‚Äù, a device that continuously measures the stream’s height, which we use to make a curve that relates stream stage to velocity throughout the summer) and standing in glacial streams, we find ourselves sprawled in a wildflower-filled alpine meadow, eating macaroni and cheese and talking about unscientific things. Does the full moon pull on the glacier the way it pulls on the tides?

On our second day, we return to the highest stake for the first time since May. We’re attached to the same rope, five meters apart and moving simultaneously across the ice, navigating mazes of crevasse fields and ice-fall. Sometimes we rearrange our rope’s trajectory to ensure we remain perpendicular to the visible crevasse patterns. We scan the glacier for stake 5 and Katie spots it at the mouth of a widening crack. Oops.

We arrive at stake 3 and the snow has melted a total of 355 centimeters in two months. The untouched field of white snow from a month prior is now striped with fissures. The crevasses concentrate in places where the glacier is moving most quickly, typically along convexities in the topography. Stake 1 is guarded by a cliff of unconsolidated sediment, the remnants of the glacier’s path, and it’s inaccessible from above. We contemplate what climbing Mount Baker will be like in 50 years, and the recently revealed uneven, unstable rocky terrain at the ice’s edges offer compelling evidence.

As we leave the glacier and return to our campsite, I baffle at the delicate heather buds waltzing in the wind. This sea of wildflowers is a product of millennia of eruptions and glaciations and burrowing marmots. I can reasonably predict what this landscape will look like when we return at the end of September, and again in February. But I can only speculate how long it will take for the summit of this glaciated volcano (currently a bright white beacon in the sky and only accessible with crampons and ice axes), to become a cirque with an alpine lake, shaded by subalpine firs and fit for hiking boots and sunset picnics.

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