Sleet and freezing rain slowed traffic and caused minor accidents north and west of Baltimore last night, but the storm brought snow to far Western Maryland where as many as 100 tractor-trailers jackknifed on Interstate 68, blocking its westbound lanes, state police said.

Light rain and drizzle was expected to continue today in the Baltimore metropolitan area and then clear for tomorrow's official start of spring.

Bill Miller, a meteorologist for the National Weather Service at Baltimore-Washington International Airport, said tomorrow will be mostly sunny with temperatures near 50.

The weekend will be partly cloudly with temperatures dropping into the low 40s.

Last night, six counties -- Howard, Carroll, Frederick, Washington, Allegany and Garrett -- had emergency snow removal plans in effect between 8 p.m. and 11 p.m.

State police at Frederick reported a woman was seriously injured last night when her car spun out of control on icy Route 26 and crashed into an on-coming pickup truck.

Police said Mary Noel Norris, 28, of the 10000 block of Liberty Road in Frederick was at Frederick Memorial Hospital today in serious condition.

Frederick Plowman, 45, of Union Bridge, Carroll County, the driver of the truck, sustained minor injuries.

About a dozen minor accidents blamed on slick roads were reported in Baltimore County.

In Allegany County, westbound Interstate 68 was closed for about two hours as police and road crews cleared numerous tractor-trailer trucks that jackknifed and blocked the highway. Four inches of snow fell intermittently between periods of freezing rain, state police said.