Here comes the slush: Rain to mix with leftover snow for flooding concerns

SEATTLE -- Seattle's weather took a step toward normalcy Monday morning with a steady rainfall instead of a heavy snow that left the region buried in several inches. But the rain comes with its own flooding headaches as it turns the snowpack into slush.

Closer to the Cascade foothills, the cold air was mounting one last stand, reinforced by an east wind blowing in chilly air from a still-frozen Eastern Washington. The layer of frigid air near the ground led to a period of freezing rain in eastern Snohomish and King County in spots like North Bend.

But so far, effects appeared to be minimal with just 4,000 customers listed without power in the foothills. Meanwhile, a last area of light snow was stubbornly clinging on to parts of Whatcom County near the Fraser River outflow with minimal accumulations expected.

The milder Pacific air was expected finally scour out those last pockets of freezing air by later Monday morning, and a Winter Weather Advisory for those areas expires at 10 a.m.

That will just leave a lot of rainfall to soak Western Washington. Forecast charts suggest around 0.50-0.75 inches of rain by Monday night, leading to potential urban flooding from melting snow and clogged storm drains.

“We suggest getting out shovels or finding a way to clear that out so that when it does rain and all the snow melts, the water will have a place to go,” said Courtney Carpenter who is a senior meteorologist with National Weather Service in Seattle.

And just because the snow has stopped, that doesn't mean road conditions have magically improved. Slush puddles will leave area roads unpredictable as well.

“It can grab your car and make you do things that can cause you to lose control,” said Trooper Rick Johnson with Washington State Patrol.

And lingering slush and snow-covered roads has left the Washington State Ferries to maintain their emergency reduced service schedule through Monday.

Residents will also keep a weary eye to trees and vulnerable structures that are now carrying the weight of both the remnant snowfall and the day's rainfall.

“That certainly could be enough to bring down some tree limbs and we'll be watching that in case they fall on any powerlines we can't rule out any kind of localized power outages going forward,” said Carpenter.

Past snowstorms in the Seattle area have been plagued with issues such as carport or marina roof collapses when we transition from a heavy snowfall to a steady rain.

So far there haven't been any reports of any major structure issues as of Monday morning but there were reports of some temporary outdoor eating areas suffering damage from snow and rain.

Five restaurants in Seattle's Fremont neighborhood suffered damage, according to Nathan Yagi-Stanton, general manager at El Camino.

Heavy snow triggering avalanche control delays in mountains

One place where snow is not giving up its grip on the area was in the Cascades, where heavy snowfall was expected at times all week and into the weekend.

WSDOT already shut down the eastbound lanes of I-90 over Snoqualmie Pass for a period at 4 a.m. Monday to conduct avalanche control.

The passes could see 15-30 inches of new snow through Tuesday night and more than 4 feet of new snow by the end of the weekend.