NORTH BEND, Wash. - An avalanche Wednesday afternoon trapped two cars, triggering a frantic search through the slide which will keep Interstate 90 closed until Thursday morning at the earliest.

"I saw the snow fall and I slammed on my brakes and I turned to the left so that I wouldn't be under the bad part of it because it was really, really heavy," said Lynette Marquis, whose car was partially buried in the snow.

The new snow slide happened about 2:45 p.m. in the westbound lanes at milepost 50, about two miles west of Snoqualmie Summit. The Washington State Department of Transportation says the slide was about 400 feet long by as much as 20 feet deep -- one of the largest natural slides they have ever seen.

Nobody in the two vehicles was hurt. Searchers with dogs used long probes to search through the snow to find other cars, but none were found.

Alex Walker says seconds is all that spared him from being buried.

"There wasn't anything in my mind other than to stay alive," said Walker."

"The snow falling around me slowed my car down enough that when I hit the side, it didn't hit very hard.  I have a tiny, tiny dent, but it's not very bad," said Marquis.

WSDOT

Two people are seen walking near the site of the avalanche on I-90 at Snoqualmie Pass on Wednesday, Jan. 30, 2008.

"It is very hard to control every area of the pass, so it's very unfortunate we did have an avalanche to come down naturally, but nobody got hurt," said Mike Westbay, WSDOT.

But when asked if the DOT still thought opening the pass was the right call, Westbay hesitated to answer.

"Let me think about that for a minute, okay?" said Westbay.

Three feet of snow has fallen since Monday and another three feet is expected before Friday, keeping the avalanche danger high.

Since the westbound lanes are blocked, plows can't get through to clear the eastbound lanes, so I-90 is closed between milepost 34 near North Bend and milepost 106 at Ellensburg and is expected to stay that way through early Thursday morning. Some truckers were allowed through the slide area and drivers stuck at the summit were allowed to go back down on the wrong side of the freeway.

The new closure came just a few hours after I-90 was reopened in both directions after being shut down for about 30 hours because of high avalanche danger.

Hundreds of vehicles, both cars and semi-trucks, finally made it through after a long wait because of an avalanche on Tuesday morning.

A 72-mile stretch of Interstate 90 between milepost 34 in North Bend and milepost 106 in Ellensburg was closed around 7:30 a.m. Tuesday after an avalanche fell on the eastbound lanes at East Snow Shed, 6 miles east of the pass.

No one was hurt in the avalanche, but the closure halted traffic on the main east-west arterial in the state.

By late Wednesday, avalanche control crews had detonated about 850 pounds of explosives in an eight-mile stretch east of Snoqualmie Pass and had removed the equivalent of 200,000 dump truck loads of snow.

WSDOT

Avalanche control crews worked throughout the day Tuesday to clear the snow on Interstate 90.

"Because of the extreme avanche danger, we're shooting the avalanches, trying to bring them down before Mother Nature brings them down herself," said Hammond. "Then we have to remove the snow - blow it, move it, shove it off and keep the freeway wide enough so the trucks and cars can get across safely."

At alternate routes at Stevens and White passes, traction tires are required, except for vehicles over 10,000 pounds which are required to have chains.

Interstate 90 normally carries about 7,000 trucks a day. The economic cost of closing I-90 is $20 million a day, according to WSDOT estimates.

KING 5's Chris Daniels, Glenn Farley and Jim Forman contributed to this report.