It's so dry in Minnesota this winter that peat bogs are burning -- an extraordinarily rare event. The Department of Natural Resources said fire fighters have battled a couple of them this year, including one they just put out that started on Dec. 26 near the gown of Gully in Polk County.
Peat is mat of partially decayed plant material, often found in wetlands or areas that used to be wetlands. Minnesota has thousands and thousands of acres of peat bogs up north. They can be anywhere from 20 inches to several deep thick, and normally it acts like a sponge, soaking up water. But now it's so dry that the upper layers of the bogs are actually shedding water, making them more susceptible to burning.
Peat bog fire near Gully, MN. DNR photo.
And once they start, peat fires can burn for years, creating huge pockets below the surface. They are also dangerous for firefighters. They smolder underground as a glowing combustion rather than an open flame. Windy conditions can move them around and bring embers to the surface where they ignite frozen grass and trees. Firefighters are at risk of severe burns on their feet and legs if they fall into pockets of burning peat.
The best way to put them out is with water. In summer, peat fires are flooded with water from irrigation pipes. Or peat nozzles, which look a lot like a metal garden wand, are inserted under the peat to shoot high-pressure streams into burning pockets. But that doesn't work so well in winter -- water and pumping equipment tends to freeze.
And unless the weather gets back to normal pretty soon, spring will be just as bad. According to the Minnesota Climatology Office, “without ample, widespread precipitation in the late winter and early spring, the state will face deficient soil moisture supplies and low water levels in wetlands, lakes and rivers.”
The frozen ground with no snow cover means more runoff in the the spring, and very little that stays behind as groundwater -- meaning more dryness and more fires.