National Weather Service meteorologist John Margraf blamed the frosty temperatures on a high-pressure system that swept cold air from Pennsylvania into the region. He predicted it would stay cold and that sleet and freezing rain would continue through the morning rush hour today.
"The temperatures dropped down really fast and they're just not going to recover," he said. "It could be pretty bad out there tomorrow."
Schools in the Tri-State area closed Thursday, and high school sporting events scheduled for Thursday were not held.
Jefferson County schools will be closed today, according schools spokeswoman Liz Thompson.
For school closing information in Washington County, parents can call the weather line forecast service sponsored by Hagerstown Trust at 301-733-3636.
Margraf said that after starting out gloomy, today's weather should brighten by this afternoon, with the sun popping out and temperatures rising above freezing.
Margraf said the sky is expected to remain clear through the weekend, with temperature climbing close to 50 degrees by Sunday.
But Thursday was no picnic. Drivers had a hard time on the slick roads throughout the day. At least eight vehicles slid off roads in the Tri-State area, officials said.
A Woodbridge, Va., man was injured at about 1:30 p.m. when the 1997 Mercury he was driving slid sideways on U.S. 522 south of the Hancock bridge and struck an embankment, said Morgan County (W.Va.) Sheriff's Department Chief Deputy Ronald McIntire.
The vehicle rolled over twice and landed on top of the guardrail, McIntire said.
"Another roll and he'd have been at the bottom," he said. "He was pretty lucky."
The driver, Mark Logan, was taken to Washington County Hospital. He was in the operating room Thursday night, according to a hospital spokeswoman.
A Watertown, Tenn., man got into an accident at about 2:30 a.m. when the truck tractor he was driving struck an embankment on the Exit 9 off-ramp in Southampton Township.
Gerald Chafee, 50, suffered minor injuries, according to state police.
The cold also took a toll on the area's homeless. A man who went to the Cold Weather Shelter in downtown Hagerstown at about 8:15 p.m. was sent to Washington County Hospital with possible frostbite, said shelter coordinator Charlie Foreman.
Area officials said that relatively few accidents were reported, however, considering the weather.
"People are either staying home or they're driving carefully," said Pennsylvania State Police Trooper Bruce Campbell of the McConnellsburg, Pa., barracks.
There was plenty of notice that the storm was heading for the area, and perhaps as a result, Thursday was fairly quite, according to officials at the 911 center in Franklin County, Pa.
On Wednesday night, members of the Chambersburg (Pa.) Borough Council and Chambersburg Area School District Board of Directors were anxious to end their meetings.
"I'm keeping the weather in mind," School Board President D. Eugene Gayman said as he tried to push the agenda along.
At the Fulton County Emergency Management Agency, a spokeswoman there said no weather-related problems were reported on Thursday.
But officials were taking a cautious approach. Lisa Sherman, the agency's director, left early for home because of the bad roads, but was available to handle emergencies through her pager, the spokeswoman said.
Rescue officials converged on a frozen spot on the Potomac River on Thursday morning for a report of a Geo Tracker on the ice.
Williamsport Volunteer Ambulance Service Chief David Hays said rescue workers went out to the vehicle, which was about 150 yards off the Maryland Shore on Dam No. 4, to make sure no one was inside.
When they reached the vehicle, they discovered it was empty and had been reported stolen in Hagerstown, Hays said.
Staff Writers Don Aines, Marlo Barnhart, Richard F. Belisle and Julie E. Greene contributed to this story.