Snow showers and slick roads early yesterday morning caused numerous accidents in the area, snarled traffic and kept some children out of school.
A weak system in the upper atmosphere, combined with northwest winds and moisture coming from the Great Lakes was just enough to cause the light snow, said Nikole Listemaa, a senior forecaster with the National Weather Service. There was little to no accumulation, she said, but temperatures in the low to mid-20s helped create perfect conditions for icy roads.
Carroll, Harford and northern Baltimore counties were hit hardest, Listemaa said.
Maryland State Police saw their first accident of the morning about 4 a.m. and within two hours had received reports of 31 weather-related crashes, a spokesman said.
Twenty of those accidents occurred on the Baltimore Beltway, and 11 were on Interstate 95, said Sgt. Thornnie Rouse. No fatalities or serious injuries were reported, he said.
The Maryland Transportation Authority police closed part of southbound I-95 near the Harbor Tunnel Thruway about 5 a.m. after the driver of a Ford Focus lost control and crossed three lanes of traffic, hitting a disabled jeep near the Eastern Avenue exit, a spokeswoman said.
Traffic was diverted to the Harbor Tunnel Thruway until I-95 was reopened about 8:20 a.m., she said.
One of the most serious accidents happened on the Beltway near Interstate 795, where a tractor-trailer jackknifed.
On Interstate 83, rush-hour traffic was backed up to Parkton in northern Baltimore County and was still crawling on the expressway and on nearby York Road as 10 a.m. approached.
The icy conditions prompted some schools to close for the day. Carroll County public schools closed at 5 a.m. for the first time this winter. In Baltimore County, high schools opened two hours later than usual, and middle and elementary school pupils, who were scheduled for early dismissal, were given the day off.
The school closings helped crews that worked through rush hour to clear the roads.
"It was a big plus for us with the schools closed to get the opportunity to get out and get some icy spots," said Kellie Boulware, a spokeswoman for the State Highway Administration.
Boulware said 300 salt trucks were dispatched in the Baltimore area early yesterday morning and continued working through about midday, although most areas were cleared by the end of rush hour, she said.
Sun staff writers Sara Neufeld and Sheridan Lyons contributed to this article.