As snow and ice melts, Glacier Park seeing new lakes
One of the new lakes below Sperry Glacier in Glacier National Park. (Joe Giersch photo)
Editor | November 21, 2023 1:15 PM
As global warming continues to shrink glaciers and ice fields in Glacier National Park, another feature is growing on the landscape — small lakes from the melting ice and snow.
Flathead Lake Biological Station scientist Joe Vanderwall has been studying these new bodies of water with great interest.
It isn’t very often that a brand new water body shows up on the landscape.
“It’s a great opportunity to study the birth of a lake,” he said, a bit tongue in cheek at the Whitefish Lakes Conference held last month.
The lakes are generally formed when the water backs up behind glacial moraines or rock formations.
Those directly below glaciers are often high in glacier flour — the highly pulverized rock formed when the ice moves against the mountain.
Glacial meltwater is high in nutrients and it doesn’t take long for different species of phytoplankton and zooplankton to colonize the waters, blown on the wind and carried by birds to the newly-formed lakes.
Phytoplankton is microscopic marine algae, while zooplankton must eat other microscopic animals or plants to survive. Vanderwall found that the phytoplankton had high chlorophyll levels than usually found — perhaps they were trying to capture as much light energy as possible in what is a very short growing season.
The lakes are often in harsh terrain, where they’re often under ice for much of the year. Having said that, Vanderwall said most likely don’t freeze from top to bottom.
Ice is less dense than the liquid water of the lake and forms top-to-bottom, which in the winter can actually insulate the lake itself once it is covered in snow, he noted in a later interview. So even moderately deep lakes can avoid completely freezing. Additionally, many of these new glacial lakes are quite deep — Upper Grinnell Lake for example is about 80 feet deep.
While the lakes are new, they haven’t found any new life forms, Vanderwall noted.