SEATTLE -- Cars slipped and buses lost control on snowy roads across Western Washington Monday as the region braced for another round of snowfall Monday night.

Forecasters said scattered snow showers are likely through Monday night and could produce additional accumulations of 1 to 3 inches in the lowlands.

VIDEO: Forecast Calls For More Snow

The new storm moving onto the coast after midnight will drop snow early Tuesday morning beginning around 1 a.m. before it turns to rain later in the morning, forecasters said. A snow advisory is in effect until 7 a.m. on Tuesday.

KIRO 7 Eyewitness News Chief Meteorologist Andy Wappler said he expects the bulk of the snow to come around midnight -- with up to 4 inches of new snow.

A Transportation Department spokeswoman, Lauren Penning, told reporters at an afternoon briefing that the department will have road crews on overlapping 12-hour shifts to keep highways clear. She said drivers should expect delays on Snoqualmie and Stevens passes for avalanche control.

DOT officials said Interstate 5 express lanes will be open to southbound traffic beginning at 11 p.m. Monday night.

They said extra crews will focus on interstates 5 and 405 near Lynnwood in the convergence zone.

On Monday, up to 5 inches of snow fell in some lowland areas, slowing travel and closing some schools.

In Bellevue, reporter Rick Price said more snow fell late Monday morning, adding to trouble for drivers who slipped on Eastside streets.

"I figured I wasn't going to be hurt because I was going too slow, but I knew I'm not going to get to work today, and I'm not supposed to be going this way on this road," said George Laws, a driver whose car slid sideways on snow-slickened South 38th Street.

Also on the Eastside, three buses slid out of control and blocked the left and right lanes of eastbound state Route 520 near Marymoor Park. All lanes were reopened by 9 a.m.

In Snohomish County, main roads were mostly clear but side streets were still slick at midday Monday, said KIRO 7 Eyewitness News reporter Chris Legeros. Some drivers had to abandon their cars; others walked.

Chopper 7 showed video of a three-car crash on Kent's East Hill. Other vehicles inched down the hill, some spinning on a glaze of ice that covered the road during the morning commute.

The Transportation Department said extra crews are out plowing snow and spreading deicer on highways across the state, focusing on interstates and mainline routes.

VIDEO: Eastside Drivers Navigate Slick Roads

Crews reopened the eastbound lanes of Highway 410 at Buckley, which was closed by snow and accidents.

SLIDESHOW: Drivers Slide On Treacherous Roadways

In the Kent Valley, Chopper 7 video showed a Metro Transit bus that had spun out. School buses were struggling in the area, said pilot Clark Stahl.

VIDEO: Snohomish County Faces Compact Snow, Ice

Heavy snow is expected in the Cascades. Six to 12 inches of snow is expected Monday night, and up to 3 feet is likely in the passes in the 24-hour period beginning Tuesday morning.