Overnight snowfall in Seattle and Portland, Oregon, and across parts of British Columbia has sent trees into the street and closed a bridge in Victoria, British Columbia.
Snowfall and travel headaches in Southern California this week were expected to linger well into the night before expanding into the Northwest Wednesday.
Heavy snow will affect the region throughout Thursday morning as much of Oregon and Washington saw a foot of snow on Wednesday. Portland saw more than a foot of snow on Tuesday.
The threat for rain and the potential for severe thunderstorms to form around the Pacific Northwest combined to create blizzard conditions in Washington and a tornado watch for the Los Angeles area.
“This will have been the most snowfall [in Seattle] in almost three decades,” said AccuWeather.com Meteorologist Andy Mussoline.
In Spokane, Washington, 18 inches of snow were measured and travel was severely impacted in the morning, Mussoline said.
However, he warned of a significant wind change for much of the region after the snow moves out.
Winds will reach 40-50 mph Wednesday afternoon, with gusts reaching 60 mph, he said. With fresh snowfall and little to no moisture in the atmosphere, the strongest winds are expected over the Cascades and peaks.
“Over Oregon and Washington, this wind is what will build the snows in the mountains,” Mussoline said.
Farther south in California, wet weather will increase over the I-5 corridor, with areas affected by flooding as rainfall totals surge above a foot.
Drought conditions across much of the state were likely to worsen, leaving even more water to drain into streams and lakes.
“The heavy rain is just coming in after a five-day span of dry weather, which created very little surface water,” Mussoline said.
Wet conditions will extend across much of California Wednesday, including San Diego.
Motorists could become stranded during the overnight hours on rain-slick roads. Motorists should allow themselves extra time for additional travel.
The prospect of an active Pacific storm through Wednesday will spread the risk of severe thunderstorms east of the Rocky Mountains.
While this will cause flooding, there will also be an increased chance of strong storms in the Pacific Northwest.
Flash flooding will become a concern across the Cascades and mountain passes. Residents along rivers should watch for rapid rises.
The region will be looking at 2-4 inches of rain across Western Washington and up to 3 inches of rain in the Cascades, most likely into Thursday morning.
Flood warnings are in effect throughout much of Washington for localized flooding of roads, small streams and low-lying areas.
“Some areas could see as much as 6 inches in the Cascades, while 1-3 inches will fall across the central valley,” Mussoline said.
Strong thunderstorms will race eastward through Oregon and then into Western Washington on Wednesday into Thursday.
While the threat for flooding exists for portions of the Cascade Range, the heaviest winds will likely be focused over the southern half of Washington, particularly across Clatskanie, Lincoln and southward through Washington City.
During the afternoon and evening hours, bursts of 60 mph wind gusts will build across the Pacific Northwest.
Some rainfall will continue to push eastward into Western Washington Thursday morning, though amounts will be light.
An additional 1-2 inches of rainfall is possible through Thursday night.
The first shot of snow could spread into the southern parts of Washington on Thursday morning, but it will mostly impact the ski resort region in the Cascades, including Snoqualmie Pass.
An upper-level low pressure will move across northern Oregon on Friday, then cross California Friday night into Saturday. It is projected to bring strong storms to the state.
On Thursday, a period of snow will remain over Southern California, but snow levels could drop to the resort areas above 8,000 feet in the Grapevine.
The system will be focused on western Washington on Friday as heavy rainfall moves into the area and begins to transition over to snow during the afternoon.
This will bring more than 1-3 inches of snowfall through Thursday night to the Cascades. A changeover to rain is expected Friday night into Saturday.