If I'm not mistaken, these are lumps thrown on top of the ditches by the snowplow, after the blizzard.

While I was making a fire in the woodstove this afternoon, Everett told me more than I ever wanted to know about the Star Wars movies. He gets very enthusiastic about such things. I nod and say "mm hm" once in a while; occasionally I ask a question, which he is invariably happy to answer.