KIRO 7 Eyewitness News reporter Gary Horcher said at first rescuers believed everybody got out safely, but after discovering a snow ski they worry a car may be trapped in the snow.

SLIDESHOW: Avalanche Covers Roadway, Traps Cars

Drivers hit by the avalanche said it felt like a massive wave and it took less than 5 seconds to cover the roadway.

As DOT crews arrived on the scene, occupants of the vehicles struck by the avalanche were outside their cars walking around.

“Because if an avalanche does come down, and you’re stuck there, stay in your car .That’s an important thing to do because if more snow comes down, you’re safer in your car than you are out of your car,” Mike Westbay with DOT said. KIRO 7 Eyewitness News was in the area of the avalanche moments before and caught up with truck drivers trying to make their way down the mountain. “Everybody wants their groceries and Nike tennis shoes and stuff like this, but they don’t understand what a driver has to go through to get it there,” truck driver Aaron Lee said.

Curtis Short and many other drivers that travel I-90 often can’t remember when snowbanks were so high.

“I mean we’re talking four-feet of snow. I’ve never seen so much snow at Denny Creek, and I’ve never seen so many trucks pulled over this early on the highway,” Short said.

Interstate 90 at Snoqualmie Pass reopened Wednesday after its longest weather closure since 2002, the state Department of Transportation said.

A major winter storm is forecast to drop 2 feet of snow on the pass starting later Wednesday, and that may force another closure because of avalanche danger, department spokeswoman Meagan McFadden said.

"If it snows as much as they are predicting, we might have to close it again to do avalanche work," McFadden said.

The state's main east-west route was closed about 7:30 a.m.

Tuesday after a snowslide blocked the eastbound lanes. It remained closed for nearly 28 hours until one lane in each direction was reopened at 11 a.m. Wednesday, McFadden said.

That's the longest since it was closed for 22 hours in 2002, she said.

Before dawn Wednesday, workers detonated about 500 pounds of explosives to bring down more loose snow and plowed enough snow and debris to fill about 130,000 dump trucks, state Transportation Secretary Paula Hammond said.

Wet, heavy snow falling on a hard icy layer created treacherous conditions, Hammond said.

Traction tires and chains were required on the pass.

More than 200 trucks were backed up Tuesday at North Bend on the west side of the pass, which is traversed by 6,500 to 7,000 trucks on a typical weekday.

To the north, U.S. Highway 2 was reopened through Stevens Pass at 6 a.m. Wednesday following three hours of avalanche control work.