Both directions of SR 20, known as the North Cascades Highway, reopened Tuesday afternoon after an avalanche blocked all lanes east of Newhalem.
The Sunday morning slide covered a stretch of SR 20 about a football field long and three stories high. WSDOT crews made good progress clearing the road Monday, opening one lane for travel.
The snow gushed across the highway like a river at milepost 122. The slide cut off access to about 60 people living in the area. WSDOT said all of them had access to food and shelter overnight as they waited the avalanche out. They were able to leave the area Monday.
Rob Mercer was traveling in the area when the slide started to cover SR 20. He captured incredible cell phone video of the avalanche in motion as it accumulated on the highway.
The Washington Department of Transportation estimated the snow slide to be 300 feet wide and up to 30 feet high.
The biggest concern was how many trees or boulders the snow took with it that may have damaged the road. Fortunately, there was very little debris.
"We need to cautiously move that snow to make sure there is no debris that could damage our equipment or injure our workers," said WSDOT's Andrea Petrich.
WSDOT crews had to stop their work mid-afternoon Monday when temperatures warmed and the avalanche danger increased.
Experts emphasize the importance of being prepared when driving through the mountain passes this time of year. They say always have extra food, water, and warm clothes with you. If you're caught in an avalanche -- stay in your vehicle and turn off your engine to avoid carbon monoxide poisoning.
There are no reports of injuries related to the SR 20 avalanche and closure. A separate avalanche on Washington's Stampede Pass killed one person and injured three others.