A few days ago Jack was held up for a couple of hours because of this avalanche that blocked the road on Atigun Pass. To me, it looks like a small avalanche. But Jack says this is the average amount of snow that usually falls on the road in this spot. Other areas involve more snow, or less.
If a truck was caught in the path of this avalanche, it could have pushed the truck over the guard rail and ended up rolling it down the hill. This is very rare nowadays since the State of Alaska does more avalanche control, shooting artillery at the mountain to dislodge the snow.
You can see the blocked road, the loader removing the snow, and also the melt water that was running alongside the road before the avalanche and which is crossing the road afterward. The last photo shows the loader dumping water as well as snow. They are best viewed if you click on the first one and scroll to the right. I had to substantially lighten the photos because of low light conditions. You can see the sun over the next hill and all the trucks waiting on the other side of the blockage. This is about 10:30 at night.