Hwy. 20 above us that winds over the Cascade mountains and passes into eastern Washington is closed seasonally. Usually around the first part of December – though depending on the weather sometimes by Thanksgiving – until April or May.
Here is why:

This avalanche – or snow slide – (I wonder what the difference is?) occurred about 13 miles up the road from us last winter.

This was a a huge slide that brought down rocks and trees and was 40 feet high over the highway.
For more photos of this slide, click on the link below.