Nearly 8 inches of snow fell at Spokane International Airport Sunday night and this morning, but forecasters were turning attention to a risk of rain and flooding Wednesday and Thursday.
Snowfall amounts varied across the region with the North Side of Spokane getting about 4 inches. About 5 inches was measured across Stevens and Pend Oreille counties this morning. A trained weather spotter five miles north of Moscow reported 11 inches of snow.
A new storm forming over the Pacific Ocean was drawing up moist air from tropical and subtropical waters, and is expected to hit the Inland Northwest with significant precipitation.
It will start as snow on Tuesday then turn to rain as temperatures rise, officials said. The rain will continue another 12 to 18 hours in waves, forecasters said.
“We’re getting into a warmer, more tropical flow,” said forecaster John Livingston.
The rising temperatures combined with rain has raised the potential for urban and some small stream flooding, Livingston said.
A flood watch was issued Monday afternoon for Spokane, Lincoln, Stevens, Pend Oreille, Garfield and Asotin counties in Washington and Kootenai, Bonner, Boundary, Shoshone, Benewah, Latah and Nez Perce counties in Idaho to run through Thursday afternoon.
However, the snowpack is so large - 25 inches this morning at Spokane International Airport - that a lot of rainfall will be absorbed by snow rather than running off and causing flooding.
But with ice on the ground, some homes could have water leaking into basements. Also, ice-clogged storm drains may not be able to drain water on streets, leading to pooling at intersections and low spots.
Motorists would be smart to avoid large puddles, and to approach them at a slow speed since water can stop an engine.
According to weather.com, “Six inches of water will reach the bottom of most passenger cars, causing loss of control or possible stalling. One foot of water will float many vehicles.”
Snowfall in the Spokane region was expected to start at about 2,000 feet in elevation and rise to 3,500 feet on Thursday. Downtown Spokane is at 1,900 feet.
To the south near Lewiston and Walla Walla, snow levels could rise to 5,000 feet.
Temperatures in Spokane are forecasted to be 40 on Wednesday and 42 on Thursday. Lewiston and Walla Walla could reach 50 on Wednesday.
Precipitation may be heavy. Spokane is forecasted to get 1.2 inches of rain or water equivalent in any snow; Coeur d’Alene, 2 inches; Pullman, 1.7 inches; Sandpoint, 3.0 inches; and 2.8 inches in the Silver Valley.
The weather service said the greatest risk of small stream flooding will be along Latah Creek, southern Spokane County, the Palouse region, Potlatch area and Asotin County.
The rain adds to concern about snow loads on roofs already sagging.
This morning, Mead School District lost the building where its mechanics work on buses. A cinder-block wall collapsed under the weight of snow atop the building, located behind the old Mead Middle School, said Wayne Leonard, executive director of business services for Mead.
Leonard said that on the recommendation of a structural engineer, the district last winter put more support beams under the building’s roof. But that didn’t prevent the wall from giving out.
The Wren Pierson Community Center in Cheney - a part of the parks system - was shut down indefinitely due to structural damage, officials said.
The Washington Department of Ecology office, 4601 N. Monroe St., was closed today and Tuesday while Washington Conservation Corps (WCC) workers shovel heavy snow from the roof, which was nearing its load-bearing capacity. Ecology staff was still available on the Web at www.ecy.wa.gov/feedback.html.
A dentist office in Colville and a barn in Stevens County were among structures with roof failures, officials reported.
This morning, the Weather Service office had 28 inches of snow on the ground with a water equivalent of 4.8 inches. That has a weight of 25 pounds per square foot.
Livingston said that the warm-up also raises the risk of ice jams on rivers, avalanches in the mountains and falling ice and snow off of trees and buildings.
He said the weather by the end of the week should calm down over the region and temperatures are expected to return to normals of 32 for highs and 21 for lows in Spokane.
“We are looking at the light at the end of the tunnel,” Livingston said about a possible pause in the record-setting succession of snow storms dating back to Dec. 17.
The Weather Service is offering experimental weather alerts on the Web at inws.wrh.noaa.gov, and a quick Web page link at weather.gov/Spokane.