1 of 4
Wisconsin State Journal, M.P. King, Associated Press
Firefighters work at extinguishing a brush fire in the state-owned Nevin Springs Fishery and Wildlife Area in Fitchburg, Wis., Tuesday, March 20, 2012.

SIOUX FALLS, S.D. — Warm, dry conditions springing from a mild winter are turning parts of the Upper Midwest and Plains into a tinderbox for wildfires.

It's an early start to wildfire season, with grassfires scorching thousands of acres, destroying rural homes and causing two deaths just this month.

Experts say three years of excessive snow and rain lead to grass growth, then this winter's relatively light snowpack allowed that tall grass to dry out. That resulted in the perfect fuel for wildfires.

Plus, the nice weather is luring people outside. Experts say the vast majority of grassfires are sparked by humans.

Fire warnings were issued Wednesday in North Dakota and Wisconsin, while a burn ban takes effect Monday in Minnesota. States spanning from Colorado to Missouri were under similar warnings earlier this month.