Look forward to your future vacation in Southwest Wisconsin and learn what Defining the Driftless is all about.
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What is the Driftless?
The land where Minnesota, Iowa, and Wisconsin meet was avoided by the last continental glacier. The area wasn’t flattened and smoothed by the glacial advance, and didn’t receive the deposits of drift, the silt and gravel, left behind as the glaciers retreated. Hence the name “Driftless”.
There are two theories of thought, that the Driftless avoided multiple ice sheets, allowing for millions of years of erosion. Or the erosion was created by the large amounts of meltwater from the last glacial period. Either way, erosion created the spectacular steep bluffs and narrow valleys of the Driftless. A landscape that is unique in North America.
Little snails, some the size of a button, were left behind as the last ice age ended and the type of species in the area changed. They are now considered endangered or threatened species. The snails are glacial relict species, and are cold adapted living only in small areas that still have the proper temperature, moisture, and food that they need. The Northern Monkshood is a rare blue flower that also only grows on rocky slopes with cool, moist habitats. It is listed as threatened.
How does the Landscape Support Ice Age Relicts?
The steep slopes and cliffs of the driftless, called Algific Talus slopes, remain cool all year. The slopes are usually north or east facing and the fractured limestone collects water which freezes in the winter and slowly melts throughout the spring and summer. A natural air conditioner for the cold adapted species. The Driftless Area is also home to sinkholes. These also cool the surrounding air. In the summertime, air is drawn down through sinkholes and over the still frozen groundwater then released through vents.
The Water of the Driftless
The porous sandstone of the Driftless retains a lot of water. The entire area is full of cold water, well oxygenated streams which spring up in coulees and at the base limestone bluffs. Water springs up in thousands of locations throughout the Driftless. These streams offer the ideal habitat for the native brook trout and the introduced brown and rainbow trout. As well as rare non-game fish and pollution intolerant invertebrates.
Another unique landscape of the Driftless is the Goat or Dry Prairie. Found on steep southwest facing slopes and with a very thin layer of soil so are easily spotted by their lack of tree cover. Inhabitants of the goat prairies are not likely to be found elsewhere in the driftless, including timber rattlesnakes and several species of lizards. These prairies are considered Globally Rare and the Driftless has an impressive number of them.