Snow, heavy at times, will continue falling in Southwest Washington into Wednesday and could bring significant accumulations to the lowlands, the Weather Service predicted Monday.
It turns out that the weekend snowfall was just a prelude to a bigger winter storm that initially had been expected to swamp the area with rain.
Monday, however, the Weather Service was alerting the public to the possibility of black ice during the morning commutes Tuesday and Wednesday and to significant snow into Wednesday.
Most local school districts had not made school closure decisions as of press time Monday night. However, Toutle cancelled classes and Castle Rock announced school would start two hours late Tuesday morning (See related link for latest school updates).
"Cold air has settled over the Pacific Northwest and will result in wintry weather across Southwest Washington and Northwest Oregon," according to a winter weather advisory the Weather Service released Monday afternoon.
The Cascade Range and the Columbia River Gorge were expected to get heavy snow Monday night, with accumulations possible in valley floors elsewhere in the region, the agency said.
Tuesday night, a strong low-pressure system will move into the region and collide with the cold air. In addition to significant snow accumulations in the Cascades and the gorge, that system "may bring significant accumulations to the lowlands as well, including the Vancouver and Portland metro area," the weather service said.
"Details are still very uncertain, especially for the lowlands, but the potential is there for this to be a significant winter weather event," the agency said.
Last week, forecasters were expecting most of this approaching midweek storm to land as rain, but cold temperatures have persisted, so showers will likely fall as snow instead of rain, said Weather Service meteorologist Liana Ramirez in Portland.
It's probable that lowland areas will get 1 to 3 inches of accumulation through Wednesday morning, Ramirez said. Areas at 500 feet or more may get another 4 inches of snow by Wednesday, she added.
The volume of snow expected is not expected to be anything colossal, but Ramirez said it will have a big impact, especially on the morning commutes.
"Black ice is a huge possibility for Tuesday and Wednesday morning," Ramirez said Monday afternoon.
Snow Saturday night and sporadic snow showers Sunday and Monday caused no major problems. Lowland streets were mostly bare and wet.
About 4 inches of snow fell in the hills around the Longview-Kelso area Saturday night.