Driftless Area National Wildlife Refuge - Chilled Air

Chilled Air

In the summer, air is drawn down through sinkholes, flows over very cold groundwater and is released out vents on the slopes. Summer temperatures on the slopes range from 42 °F (6 °C) to 55 °F (13 °C). In winter, the air is drawn into the vents, and the groundwater again freezes. Because of the cool temperatures and moist conditions, unusual plants for this part of the country grow on the slopes. Typically growing in a colder more northern climate, yews, balsam fir, Showy lady's slipper and golden saxifrage can be found on the cool slopes. These cold microclimates of the slopes allow the rare plants and animals to survive.