Dry conditions not the sole cause, however, as largest fire was intentionally set.

Between extinguishing and containing fires and responding to other calls, this past weekend was one of the busiest ever for Crookston firefighters. While the extremely dry weather conditions played a role in the blazes, indications are that something more sinister was at work behind some of them.

The whirlwind of suspicious fire activity began Friday night when the fire department was called to a grass fire in Andover Township at around 10. After three hours passed, firefighters found themselves extinguishing another grass fire along the railroad tracks on South Main Street. The big one, some 80 acres of primarily state-owned land in Onstad Township southeast of Crookston, came only an hour later and kept several agencies hopping throughout the weekend.

Firefighters backburned the area to contain the blaze. At about 6 a.m. Saturday, the Crookston Fire Department turned the matter over to the Department of Natural Resources, which in turn brought in other area wildlife firefighting resources including the Bagley Forestry Office. The CFD is continuing to provide water for firefighting efforts and has returned to the scene a few times to do so.

"I spent 12 hours out there Saturday, mostly watching for underground fire activity," said Ross Hier, acting area wildlife manager out of the Crookston DNR office. "Peat bogs, organic soil and other material underneath is highly susceptible to reigniting because it's so dry. So we need to continuing monitoring this for at least a week, most likely longer. You need to go in there right after dark to see the smoke from any underground fire activity."

The fire, which Hier said was "most definitely arson," burned approximately 80 acres of land in the Foxboro Prairie Unit of the Pembina Trail Preserve Scientific and Natural Area and another five acres of private land across the road. This amounts to half of the Foxboro Unit (there are three units in the Pembina Trail Preserve SNA). Foxboro is located off County Road 44, between Highway 2 and 102.

According to the DNR, the SNA program "preserves natural features and rare resources of exceptional scientific and educational value." They are open to the public for nature observation and education. The Pembina Trail SNA is managed through the Northwest Region out of Fergus Falls. A portion of the site is owned by The Nature Conservancy.

Hier noted that another fire occurred three weeks ago in the Shypoke Wildlife Management Area in Godfrey Township, about three miles from the Foxboro Unit. This one involved a smaller amount of private and public land, where lightning had evidently struck a week earlier before the flames let loose. Although there were some underground fires, it's been quiet for the last week.

"We're crossing our fingers that the fire activity is done and we can get through this red flag day," he said. "But everything is still being monitored until we're confident the danger has passed."

Those dealing with the fires are hoping for cooler, moister air to descend upon the area, and soon.

"I didn't think I would ever be asking for a good four inches of rain, but we need at least that," said Hier.

"Cold and snowy would be nice, although some people out there might disagree," said Crookston Firefighter Bob Magsam.

The Crookston Fire Department and Polk County Sheriff's Office are investigating the fires and will release information soon.