Wisconsin caves
Wisconsin has no "mammoth" caves. The thinness of its dolomitic bedrock, the glaciation of much of its area, the periglacial effects of runoff, frost action, and subsequent erosion have all contributed to the smallness and paucity of its caves. Where it might once have possessed large cavern systems, the cyclic return of the glaciers managed to crush and fill them. Where the direct action of a glacier has not recently occurred -- in the so-called "Driftless Area" of southwestern Wisconsin -- the runoff from the glacier melt eroded away the cavern systems with much the same effect. As a result, the state has very few caves, all small in size.... Well over 250 caves have been catalogued in the state. A high percentage of these are small erosion caves in sandstone -- over half the known caves in the state are under 100 feet in length --but the longer caves ... are as interesting as the much larger caves outside of Wisconsin.
(William Cronon in "An Introduction to Caves of Minnesota, Iowa, and Wisconsin", pp.105,106)
The caves in southwest Wisconsin have little in the way of water, mostly puddles, and have a temperature of 45 to 50 degrees.
Please note that caves vary across the country. Being a competent Wisconsin caver does not mean that one can cave safely anywhere else.
