For winter sports enthusiasts, this year's snowpack has proven less than ideal. Summit County's first few inches of backcountry snow, typically the first of many quick-falling layers, were instead beaten down by too many days of clear skies and erratic temperatures. This created a very weak base layer of snow full of poorly bonded, sugary snow known as “depth hoar.” Now, the new snow we're so happy to see at long last is falling on top of this very fragile layer and creating potentially dangerous conditions for those who wish to travel and play in the backcountry. However, not all Summit County residents are cursing the hoar.

In fact, that space between the warm ground and the snow above, known as the subnivean (literally, “under snow”) zone, creates a haven for many of Summit County's year-round residents. Small animals such as voles, mice, red squirrels and pika are among a small contingent of creatures who quietly take up winter residence in the insulated space between the earth and the snow cover. The loose, porous quality of depth hoar make tunneling, den building, foraging and hunting for food a breeze.

Earlier this season, as I walked around campus with a group of students at Keystone Science School, we stopped several times to view the tiny entryways to the vast tunnel system that is the subnivean world. Envision yourself for a moment as Pac-Man, cruising through this maze of tunnels. You would witness vertical shafts that supply fresh air, plants that remain green all winter long (such as kinnikinnick), and a temperature that hovers around 32ºF regardless of the air temperature above. However, being insulated from the outside elements does not mean you are immune to those elements.

Although the snow to some degree hides these subnivean creatures from supranivean (above snow) predators such as the weasel, coyote and fox, these hungry hunters have adapted in their own way. Weasels are long and slender, perfect for infiltrating subnivean tunnels. Fox and coyotes use their keen sense of hearing and smell to identify and pounce upon small critters scurrying under the snow.

As winter progresses and our snow pack increases (and hopefully settles), think about what might be going on under the snow. When you're out hiking or cross-country skiing, look for snow holes surrounded with midden (scattered remains of pinecones) and you will know a red squirrel has been there. Keep your eyes peeled for signs of fox or coyote tracks that form a circle; chances are they were stalking some small prey. And when spring eventually comes, carefully check your yards or nearby fields for the melting remnants of that vast subnivean tunnel system, remembering that it brought warmth and protection to many tiny creatures in the depth of icy winter.

Tyler Bunnelle is a program instructor at Keystone Science School. To learn more about our programs, visit www.keystonescienceschool.org.