Steamboat Pilot & Today

Steamboat Springs — Though the snow-covered terrain of the Routt National Forest may appear to be a still, seemingly lifeless environment to humans, underneath the snow proves to be a whole different story.

Biologist say one of the most active winter environments in the Rocky Mountains is under the snowpack.

"Most people are unaware of the world below. It's fascinating," U.S. Forest Service wildlife biologist Rob Bringuel said.

Snow creates an insulating blanket on the ground that slows the natural loss of the earth's heat, he explained.

In other words, the bottom of the snowpack is warmer than the surface. Though it doesn't get above freezing, it also doesn't get below 15 degrees. That's warm enough for small mammals to adequately spend an active winter in.

"It provides many small animals with a relatively warm, stable environment," Bringuel said.

Voles, shrews, pine squirrels, pocket gophers and mice are just a few of the animals considered to be subnivean, meaning they live under the snow.

The animals don't hibernate under the snow; instead they tunnel through the snowpack looking for insects, plants and roots for food. They create caches, build nests and find mates.

There are subnivean predators as well, such as the short-tailed and the long-tailed weasels. The predators often follow the tunnels of rodents, hoping to find a quick meal.

Bringuel explained that small mammals proportionally have to eat more food than larger mammals to keep warm and stay alive in the winter. So it's vital that they actively feed and live during the winter, even if it means under the snowpack.

"The air below the snow is saturated with moisture. That helps the animal. They don't have a high requirement for water," Bringuel said.

Holes and tracks in the snow near down logs and trees are the signs of the subnivean life.

"They will come up above ground when the weather is nice," Bringuel said.

But for the most part, the animals spend most of the winter under the snow.

There isn't much known about the subnivean environment or how human recreation on the snow affects it, Bringuel said.

"We know it as an affect and it's probably and adverse affect, but we don't know how much yet," he said.

He said there are some ongoing studies in other national forests looking at the affect of the winter recreation on the subnivean environment.