How glaciers carved Lake Louise & the Rockies: what remains today

Everywhere, the Canadian Rockies are scoured and marked by the power of ice. We have these powerful glaciers to thank for much of the beauty we now enjoy. Banff NP’s Lake Louise at 1,731m elevation is one example of one such famous site created by glacial erosion.

The Victoria Glacier above the head of Lake Louise, feeds the glacial lake with meltwater.

Above the head of the lake lies Victoria Glacier, a valley glacier, which feeds Lake Louise with beautiful blue-green meltwater (Britannica). Years ago, the Victoria glacier probably once extended much further into the valley while only a fraction of it remains today.

The end of the trail approaching the head of Lake Louise. Beyond this point the trail crosses avalanche paths. It appears not everyone heeded the warnings; see footprints litter the snow just beyond the sign.
The mini-avalanche we witnessed at Lake Louise still roared and crumbled despite the small size of the collapse. I still wouldn’t want to be anywhere near it! These falls must happen regularly based on the debris pile at the bottom. Spring is avalanche season in the mountains.

You can get closer to the  Victoria Glacier on the Plain of Six Glaciers trail, but the latter part of the trail was closed to us (like a few others on our trip) due to potential avalanches. In fact, while we walked along the frozen lake, we witnessed a mini-avalanche on the opposite shore.

Lake Louise still frozen in late April.

Even when frozen, the lake’s waters are blue because it is a glacial-fed lake. As glaciers grind up rocks above the lake, fine glacial silt is created and deposited into the lake by meltwater. The sediment is then suspended in the lake as it slowly settles to the bottom and the sunlight reflects off the sediment is what gives it such rich hues.

As we walked along the lake, Golden-mantled Ground Squirrels scurried along the edges of the frozen lake while Clark’s Nutcrackers were unperturbed by tourists, seeking out an easy meal.

The small Golden-mantled Ground Squirrel, commonly confused with a chipmunk!
Clark’s Nutcracker, not at all bothered by the noisy tourists.

While much of the ice that once existed is now gone, glaciers still persist in the Rockies high in the mountains and down alpine valleys. At 2,800m elevation, the Columbia Icefield exists today due to the buildup of the annual fall of 7m of snow; the accumulation of snow over time forms the icefield (Parks Canada).

Perched along the Continental Divide, the approximately 215 square kilometer icefield is a major source of freshwater in North America (Gadd, 2008). The Athabasca River, the North Saskatchewan River and the  Columbia River are all sourced from the icefield, their waters eventually reaching the Arctic, Atlantic and Pacific Oceans, respectively.

Part of the Columbia Icefield in Jaser NP, AB. The Snow Glacier is the lumpy looking snow on the right of the photo. To the left of the glacier is the Snow Dome at 3,456m elevation which lies directly on the Alberta-British Columbia border.

From the top of the Icefield, seven valley glaciers flow downward, one of which is the easily accessible Athabasca Glacier. The Athabasca Glacier is currently retreating although it once reached as far as where the Icefields Visitor Center stands today (Gadd, 2008).

The Athabasca Glacier, Columbia Icefields, Jasper NP, AB.

While glaciers are mighty erosive forces, they also deposit incredible loads of sediment. By studying the erosive features and deposits left behind by glacier, geologists can determine how far the glacier extended in the past.

athabascaglacier
The Athabasca Glacier valley with some glacial features labelled. Glaciers scour through rock, leaving behind characteristic round-bottomed and steep-sided U-shaped valleys as opposed to rivers cutting out V-shaped valleys. (Click for full size image)

The Athabasca Glacier valley where the U-shape of the valley is clearly seen. Lateral moraines are piles of rock debris deposited along the edges of a glacier as it recedes. Here, they mark where the glacier extended much wider into the valley than it does today, almost outlining the glacier’s previous boundaries.

The rocky debris in the foreground of the photo (a recessional moraine) was deposited as the glacier retreated from a former position further into the valley; the land where I stood taking this photo was once covered by ice as recently as the early 1800s (Patton, 2014). A glacier retreats when melting occurs faster at the toe than snow and ice can accumulate further up on the glacier. Basically, it is like simple math. If what goes in (snowfall) is less than what goes out (melt), the glacier retreats.

The North Saskatchewan River flows from the Rocky Mountains east toward Lake Winnipeg, its waters eventually reaching the Atlantic Ocean at the Hudson Bay via the Nelson River (Jasper NP, AB).

Freshwater is a critical resource not only for human survival, but flora and fauna of all kinds, and the Columbia Icefield is an important resource for all living things besides its simple beauty. The melting and building of the Columbia Icefield impacts what happens downstream in the Columbia River and as far away as the Arctic Ocean where the Mackenzie River (the largest and longest river in Canada) empties into its seas.

All things in nature are inter-connected. Wildlife is wild. When will more people realize this? Animals and plants do not recognize park, provincial or national boundaries. Wolves and bears protected within the park boundaries wander out where they are hunted and killed because legislation permits hunting these animals. Pollution does not stop at the border with Alberta because it is from British Columbia. Invasive species from the U.S. do not stop at a border crossing with Canada to get their passport stamped and approved. When will people work together as stewards and take responsibility for our impact, both positive and negative, on this earth before it is too late for everyone, including ourselves?


References
Columbia Icefield and Athabasca Glacier, Parks Canada
Gadd, B., 2008. Columbia Icefield, Athabasca Glacier in Canadian Rockies Geology Road Tours, pp. 335-342.
Lake Louise in: Encyclopedia Britannica
Patton, B., 2014. Icefields Parkway Driving Guide in Parkways of the Canadian Rockies.

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