carvalanche

It's winter, it's been dumping all night, and you now have a foot of snow on the roof of your car. You're driving somewhere, hit the brakes, and all the snow on your roof slides forward and buries your windshield. You've just been hit with a carvalanche!

See also fenderberg.

Me: I was heading up to the mountain for first tracks, but some flatlander in an SUV cut me off and I had to hit the brakes.

Friend: Did it trigger a carvalanche?

Me: Totally! My windshield was BURIED!