One day after a Wednesday snowstorm tied up morning traffic on Interstate 90 in Spokane, forecasters were predicting that much of the snow pack below 4,000 feet in elevation will succumb to rain and milder temperatures by Friday.
The melting snow may send a flush of water into creeks, streams, catch basins and fields.
“We are going to warm up and we are going to stay warm until Tuesday,” said Ron Miller, forecaster for the National Weather Service.
Four to 5 inches of snow blanketed the Spokane and Coeur d’Alene area by noon when a light period of freezing rain put a thin crust of ice on top of the snow.
Spokane International Airport measured 3.9 inches from the storm. Nearly 6.5 inches fell on parts of Coeur d’Alene by 6 p.m., according to the weather service.
During the morning commute, traffic westbound on Interstate 90 was backed up as far as five miles.
The Washington State Patrol said the problem was caused by a crash involving a semi truck and two vehicles about 6:36 a.m. That accident blocked two of three lanes.
The backup kept getting longer and longer for two hours until lanes were reopened shortly before 9 a.m.
During the traffic jam, a lot of the inbound freeway traffic exited onto Second Avenue and Hamilton Street to avoid the congestion to the west.
A slowdown was also reported earlier on I-90 near Sprague Avenue.
A stream of moist Pacific air is expected to bring a series of rain storms through Sunday along with breezy winds and highs in the 40s.
Overnight lows should be in the middle to upper 30s through Sunday night.
“We are going to be warm and windy. We are going to see some pretty good melting,” Miller said.
Monday should see a 40 percent chance of rain and a high in downtown of 43 degrees.
Coeur d’Alene will see similar weather.
As a result, forecasters have shifted their attention to flooding concerns.
A hydrology forecast Wednesday afternoon said, “Runoff from melting snow and rainfall will cause significant rises in rivers and streams, particularly in the Palouse, Coeur d’Alene and Spokane basins.”
Ice jams may create localized flooding, the forecast said. Also, water may flood low-lying fields and create hazards on roads. Urban areas could see pools of water along streets due to blocked drainage ways.
Snow is expected mostly at ski areas and upper slopes.
The Idaho Panhandle National Forest issued a high avalanche alert Wednesday for the mountains of the region.
An avalanche watch was issued for the mountains to the northwest of Chelan and Wenatchee.
The city of Spokane declared a stage-1 snow emergency and mobilized 48 plows and de-icer trucks. The emergency seeks to get owners to move vehicles off arterials, bus routes and hilly streets.
Some flight delays occurred at Spokane International Airport, but no cancellations were posted by midmorning.