SEATTLE – Blizzard conditions and avalanche danger in the Cascades overnight forced the Transportation Department to close Snoqualmie, Stevens and White passes.

While, US 2 through Stevens Pass and US 12 through White Pass are closed, transportation officials re-opened I-90 at Snoqualmie Pass Thursday morning.

They warned, however, that it could be closed again — temporarily or indefinitely — because of the treacherous avalanche conditions and foul weather.

The National Weather Service issued an unusual blizzard warning through Thursday afternoon for the north and central Cascades and predicted 15 to 30 inches of new snow in the mountains by Friday morning.

A high wind warning is also in effect for the Strait of Juan de Fuca to Admiralty Inlet, the west side of Whidbey Island, western Snohomish County northward through Thursday afternoon.

A cold front brought heavy snow to the mountains and strong south winds to the coast and lowlands overnight Wednesday. Wind gusts clocked in at 57 mph at Westport, 52 mph in Tacoma and 45 mph in Seattle in the early hours Thursday.

"The goods news: the winds have peaked out several hours ago and they're slowly diminishing," said KING 5 Meteorologist Rich Marriott. "You're going to go through spots where it's gusty and spots where it's fairly calm this morning, but overall the winds will be diminishing."

The National Weather Service says a series of fronts will cross Washington in the next few days bringing more rain to Western Washington and snow to the mountains and Eastern Washington.

Marriott expected 10-18 inches of snow to fall in the next 24 hours in the mountains. Avalanche crews will be up on the slopes setting off explosions to keep the chutes free of sliding snow and the road safe. Just the rate that the snow falls will make avalanche controls difficult.

Much of the day Wednesday I-90 was bare and wet, with traction tires advised. But plow drivers were on the road, trying to get off everything they could for the next round.

Over the last two weeks, about 386 inches of total snowfall has fallen at Snoqualmie Pass, creating a high avalanche warning for the Cascades. In February alone, nearly 122 inches of snow has fallen so far. That's up there with the major snow fall of 1996, when nearly 104 inches fell in February.

"It just keeps getting higher and higher and they haven't had that natural compaction of the rain coming down. So that's what's causing the high avalanche danger, keeping the light fluffy snow," said Erin Bogenschultz, DOT spokesperson.

Another issue is the shear amount of snowfall and where to place it all. 

"We've got the build up of snow," said Bogenschultz. "It's so high, we're still having to truck a lot of that snow out, and our snow storage areas are really full right now."

Eastern Washington

In Eastern Washington, forecasters have a winter storm warning in effect for the Spokane area, Palouse and northeast mountains. There's a high wind warning in effect for the lower Columbia Basin.

A number of highways in Eastern Washington, including U.S. 2 west of Spokane and U.S. 195 south of Pullman, were closed overnight because of blowing and drifting snow.

KHQ Television of Spokane reported early Thursday that a roof collapse at a Northwest Bedding store in Airway Heights, west of the city.

On Wednesday night a 50- by 60-foot section of roof collapsed at Fire Station 82 in Valleyford, southeast of Spokane, as six workers were removing snow. Two fell 12 to 14 feet to the floor but escaped injury and the other four were on a part of the roof that remained in place, said Deputy Chief Lonnie Rash of Spokane County Fire District 8.

The cave-in occurred five hours after the building was evacuated and vehicles were removed because of cracking noises from the ceiling, Rash said. The workers were from Belfor Construction Services, which was hired to check on the roof.

Rash estimated the snow on the roof was half of a foot to 2 1/2 feet deep on the roof, which is supported by a webbed truss. The part that collapsed was over the bay where four trucks are normally parked.

"I would imagine this fire station will be out of service for a while," Rash said.

The weather figured in a number of traffic accidents, including one in which an eastbound tanker carrying more than 7,000 gallons of raw milk on I-90 apparently hit an icy stretch and overturned early Wednesday morning in the Four Lakes area west of Spokane. The driver escaped with minor injuries but much of the milk was spilled.

"I wish someone would bring some Oreos," State Patrol Trooper Todd Kerbs said.