The National Weather Service confirmed Monday that a tornado touched down Sunday night in the Clark, South Pymatuning and Delaware Township areas.

Winds that leveled homes, toppled utility poles, signs, cable and power lines and tossed cars around like toys reached close to 155 mph, officials from the service's Pittsburgh office said.

The National Weather Service classified the tornado as a strong F2 -- just shy of an F3. The service rates tornados on a scale that ranges from F1 through F5, which is the most vicious.

The tornado -- which killed Charles E. Thompson, 81, of 22 Milton St., Clark, when his house collapsed -- was spawned by a weather system that swept through more than half a dozen states from Alabama to Pennsylvania, killing at least 34 others people and injuring more than 200, including 18 locally. Six homes in the borough were completely destroyed and at least 25 others were severely damaged.

The funnel cloud, which was 500 feet wide at its widest point, hit shortly before 8 p.m. Sunday, according to Rich Kane, National Weather Service meteorologist.

The tornado pattern appears to have stretched out from South Pymatuning Township, Kane said. It touched down between Clark and Hermitage before widening out and striking Clark. The twister also caused tree damage around Shenango River Lake and in Delaware Township. In some areas the twister left a path of destruction four miles long.

Kane said most tornadoes occur in late May and early June, with stronger ones often occurring earlier. November is not an ideal time for a twister, but he said the atmospheric pressure peaks that cause tornadoes can occur in autumn, since the atmosphere can mimic conditions in spring.

Jefferson-Clark police Chief Jeff Lockard said all residents were accounted for Sunday night, which was the primary goal of rescuers on the scene.

Of the 18 injured Sunday, 10 were treated for injuries at a temporary shelter, four were taken to UPMC Horizon, Greenville, three to the hospital of the Sharon Regional Health System and one to UPMC Horizon, Farrell, Lockard said. One of the victims was later transported from Sharon Regional to St. Elizabeth's Health Center, Youngstown, he said. None of the names of the injured were released.

Six homes in the borough, four of them on Milton Street, were ruled completely destroyed, Lockard said. Many other homes endured heavy structural damage though officials couldn't say how many.

Clark fire officials weren't able to set off the town's alarm system before the tornado hit because the power went out, silencing the siren, Lockard said. Neighboring Delaware Township has no sirens. Officials said the National Weather Service also issued a warning over the radio at the same time an alert went out over the county's emergency warning system.

"These things happen very quickly," said James Thompson, Mercer County director of public safety. "It's a matter of a few seconds."

Kane said people should take tornado warnings or any type of weather warning or watch seriously. "This could happen any day of the year -- night or day," Kane said. "Everybody should have a plan of action. You should know what to do and where to go."

Crews worked into Monday clearing trees and debris from roads and checking on gas leaks reported in the area.

David Bollenbacher, PennDOT manager, said four crews armed with chain saws were sent out overnight Sunday to help clear roadways. He said they would be on the job all week long.

Sgt. Pete Calenda of the Greenville-West Salem Police Department, was among those who responded to the disaster Sunday. He said local police and firefighters searched the area for people who needed help and guarded the area to keep looters and onlookers out.

Calenda said he helped pull Georgette Templeton, the dead man's wife, from the wreckage of her home. A gas leak hampered the rescue, he said.

"It could have been a lot worse," Calenda said. "It was Sunday night, and many people were at home. They made it to their basements, and that's what saved them."

Thompson said a county damage assessment team was deployed Monday to compile a report.

"Mercer's been hit pretty bad this year," Kane said, referring to straight line winds that damaged homes and trees in South Pymatuning Township in April. "It (the county) has the dubious honor of having the strongest tornado in Pennsylvania from back in '85," Kane said.

In May 1985, a tornado struck Wheatland, Hermitage and Atlantic in Crawford County. As many as 12 people were killed and an estimated $25 million in damage resulted. Kane said that tornado was classified as F5.