All snow humans know about roof avalanches. Â You have to make damn sure that you don’t end up under them when they happen. Â It’s good to make sure your car isn’t under them either. Â They can be destructive and they can be cute. Â This video shows us one that is just plain bizarre. Â The square chucks of snow coming off the roof here in Grapevine, Texas seem perfectly uniform and they resemble square plastic plates more than snow.