POPLAR GROVE - A freak January tornado moved through Illinois Monday, destroying buildings, toppling trees and knocking railroad cars off the tracks before moving into Wisconsin, emergency workers said.

The National Weather Service said it received unconfirmed reports of two touchdowns in Northern Illinois, one in the rural village of Poplar Grove and the other north of the city of Harvard, about 13 miles apart. A third reportedly touched down in Tazewell County here in Central Illinois.

The storm that ran through Poplar Grove left three people with minor injuries, said Boone County Sheriff's Lt. Perry Gay. Six or seven homes were destroyed; a number of sheds and barns were destroyed as well, but Gay did not know how many.

A sheriff's deputy spotted a tornado on the ground at about 3:30 p.m. about 1 1/2 miles north of Poplar Grove, Gay said. According to the 2006 Census, the village has about 3,500 residents.

"Had the tornado been a little bit south, it would have been smack dab in the middle of the village, which also has a lot of businesses," Gay said. "We were very fortunate it hit on the outskirts."

Rescue crews planned to spend Monday night making sure no one was trapped in debris, but authorities believe the destroyed houses were unoccupied when the tornado struck, Gay said.

Authorities also had to help people who were in trapped cars surrounded by live electrical wires, Gay said. Numerous roads were closed because of downed trees and electrical wires, he said.

Union Pacific spokesman Mark Davis said no one was injured when one locomotive and 12 freight cars derailed Monday around 4 p.m. in Harvard in McHenry County.

One tank car, which leaked for hours before being contained Monday night, contained shock fluid, Davis said. Another tank car that ended up on its side contained ethylene oxide, a flammable material widely used to sterilize medical supplies, but a Union Pacific manager on the scene determined that tank was not leaking, Davis said.

Authorities ordered the evacuation of about 500 residents in the nearby unincorporated town of Lawrence because of the potential for a hazardous materials situation, said Capt. David Shepherd with the McHenry County sheriff's office. No injuries were reported, he said.

Three other derailed cars on the train headed to Janesville, Wis., from North Lake contained auto parts, and seven more were empty, Davis said.

Crews prepared Monday night to move the cars away from the tracks.

"It's very muddy conditions in the area, so it'll take a while," Davis said.

No one was injured when wind gusts as high as 60 miles mph ripped through Tazewell County Monday evening and destroyed a pole barn, said officials with the Tazewell County sheriff's office.

Bill Lischka saw the tornado form as he sat drinking coffee at the Boone County Family Restaurant in Caledonia, near Poplar Grove.

"A tornado just popped right out of the clouds," he said. "Just a classic twister."

Lischka said the funnel looked like "a snake dangling" as it wove its way north and east. He didn't see the tornado touch down but said he has heard about damage to several businesses and homes.

The last time a tornado touched down in January in north-central or northeastern Illinois was Jan. 25, 1950, according to the National Weather Service.

That tornado hit Manteno, in Kankakee County, about 50 miles south of Chicago.

On that day in 1950, the air was warm and moist, and Chicago hit a high of 67 degrees, weather very similar to what Illinois experienced Monday, said NWS meteorologist Eric Lenning.

Northern Illinois is usually free of tornadoes in the winter because colder, more arctic air sits over the region, Lenning said. Tornadoes need warmer temperatures and moist air for support, conditions located much farther south in the wintertime.

But for the last couple of days, "we've had spring-like weather. That's when we'd normally expect this kind of (severe) weather," Lenning said.