By James B. Kelleher and Brendan O'Brien
(Reuters) - The unseasonably warm weather giving many residents an early taste of summer has raised the danger of wildfires in some northern parts of the country where such fires are unusual, officials warned on Wednesday.
In Wisconsin, where several grassfires over the past week claimed hundreds of acres and were blamed for two deaths, the Department of Natural Resources issued a high and very high fire danger alert for half the state.
The National Weather Service also issued fire weather watch warnings on Wednesday for parts of North Dakota and Montana.
Forecasters said the current warm weather and low humidity, combined with the unusually mild and dry winter, had turned vegetation in many areas into kindling that easily could be set alight by lightning strikes or human carelessness.
The Weather Service said the risk in North Dakota and Montana would be especially high on Thursday because gusty winds out of the southeast, kicked up by the storm that moved into Louisiana, Arkansas and Mississippi on Wednesday, would "increase the potential risk for explosive wildfire growth."
"If the winds are strong enough and the humidity is low enough, when a fire does start it can quickly get out of control," said Ken Simosko, a meteorologist in the Weather Service's office in Bismarck, North Dakota.
On Wednesday, about 170 small wildfires were still burning on about 300 acres across the state of Wisconsin, which is now entirely snow free -- a rarity this early in the year.
"Weather in Wisconsin is kind of crazy these days," said Catherine Koele, the state's Department of Natural Resources wildfire prevention specialist.
"Typically we see drought conditions in the summer months, but that could be earlier because of the earlier warmer temperatures," Koele said.
Wisconsin officials are also concerned about the residual effects of a windstorm in the northwestern part of the state last July. The storm left about 130,000 acres of downed timber in five counties.
"It poses a huge fire risk," Koele said. "They got some rain in a last couple days, which is really great. But going forward, the fire risk is really a problem."
The unusually mild winter, which has left a parched landscape behind, is as much to blame for the fire danger as the current warm weather and low humidity, forecasters said.
Wildfires were a major problem last year in the Plains states and the Southwest, especially in Texas, New Mexico and Arizona where millions of acres were scorched. But wildfires are unusual in states such as Wisconsin, where rainfall snow totals are typically much higher.
One measure of just how mild the past winter was came from Minneapolis on Wednesday, where officials said it was unlikely there would be any snow emergencies declared in the city for the winter season that ends there officially on April 1 -- the first time that has happened in 25 years.
About 22 inches of snow have fallen on the city this winter. Last year, Minneapolis was hit with nearly 87 inches of snow and officials declared eight snow emergencies.
The unusually warm weather continued on Wednesday across much of the eastern part of the United States and Canada, with new record highs set in a host of cities, including Milwaukee, Grand Rapids, Michigan and Buffalo, as well as Timmins, Ontario and Montreal, Quebec, according to AccuWeather.com.
Today's high in Timmins was 80 degrees -- nearly 50 degrees above the normal high for this time of year of 32 degrees, according to AccuWeather.com.
In Chicago, which has now enjoyed eight consecutive days of record-breaking temperatures, the afternoon high of 84 degrees was 35 degrees above the normal for this date, according to AccuWeather.com.
Chicago's record high for March, 85 degrees, was set on Tuesday.
"The amazing thing is some of these places are close to relatively chilly Great Lakes waters and they're still hitting these highs," said Alex Sosnowski, a meteorologist at the private forecasting firm.
(Additional reporting by David Bailey)