Winter snowpacks often lead us to the impression that the ground is dead beneath this blanket of white. In reality, there is plenty of winter activity beneath the snowpack.

During early winter, you may see signs of mice and voles traveling across the snow surface in search of food, but after the snowpack reaches between 15 and 25 cm, they retreat under the snow. For the remainder of the winter, they'll forage at ground level. Eventually, they'll establish a series of runways that allow them to move around freely. Unfortunately, the snows this year have not made their runway construction easy. On cold years with strong depth hoar formation, it's fairly simple to move about, however this year the weather has not cooperated. Shallower than normal snowpacks do not provide the same amount of protection from the cold. During our recent snow storm, it was not only the skiers rejoicing, but all the tiny furry creatures that live beneath the snows as well. The pika is another animal that spends the winter traveling under the snow (known as the subnivean environment). During the summer it constantly collects plants to help it get through the long winter. They need a good supply to last them well into the spring as they live at high elevations where the snowpack is the heaviest.

One of the biggest dangers to subnivean animals is an early cold spell. If the temperatures turn cold before the snow is deep enough to provide ample insulation, there can be a large die off of both plants and animals that rely on the snow for protection from the cold.

Once the runways have been developed and enough snow accumulated to provide a constant near 0°C temperature, they can remain fairly active through-out the winter with little worry of blizzards and bottomless snow. They are not completely free of predators though as animals like the coyote and the snowy owl are quite adept at tracking down their dinner right through the snow.

The pine marten is another animal that takes advantage of the subnivean environment. Martens live in old growth forests with a complex landscape of down and dead wood. These fallen logs make it easier for the marten to escape beneath the cold temperatures above the snow. Since martens, along with the other subnivean creatures, are quite small in size, they lose heat quickly. Removing deadfalls can reduce the ability marten's ability to escape from the cold.