The Lewellyn Glacier

As it formed on mountainsides and moved down the valley the Llewellyn is called an alpine glacier. This movement down the valley deepened it greatly by pushing dirt, soil, and other material out of its way. This deep valley filled with glacier melt waterm creating the beautiful wide, deep and colourful Atlin Lake. As it melts the glacier provides fresh water to Atlin which feeds into the Yukon River. A major fresh water source in the Yukon and Alaska.

Glaciers form when snow piles up faster than it melts which can only occur when the accumulation of snow is not lost during summer months. Temperatures must remain low year round. Accumulation must also repeat for multiple decades with significant snowfall consisting of ice, snow, rock, sediment and water. The snow then compresses and becomes dense forming ice and under the weight of the ice beings to move down slope, down a valley.

Glaciers move across mountains and valleys because snow doesn't fall evenly and ice forms at different rates along with ice melting at different rates, the density of the ice varies across the glacier. Also different parts of the glacier moving at different speeds with the ice in the middle moving faster due to less friction. Ice at the base moves more slowly because there is more friction as it moves along the rocky bed. The difference in the movement cause tension to build in the upper part of the ice and factures the ice to form crevasses. These crevasses can be very deep.

Glaciers are also heavy and exerts pressure causing snow to melt without any increase in temperature. The meltwater makes the bottom of the heavy glacier slicker and more able to spread across the landscape.

Even though glacier move very slowly they have a lot of power as they bulldoze, crush, grind and move everything in their path. They hollow out a path as they move forward forming and then recede leaving dramatic landscapes. You can see evidence of this everywhere you look in the Atlin/Téix’gi Aan Tlein Provincial Park from erratics (rocks that are deposited away from the glacier and differ significantly from the landscape where they are deposited), moraines (piles of rock, dirt and gravel dumped at the glaciers end, edges, and center of the glacier), striations (long grooves created by large rocks pushed along the bottom on the glacier. They can help determine the direction of the glaciers travel) and Atlin lake (depression dug out from the glacier and filled with glacier fed water).