Snow Rollers
Weird Snowballs
These usually occur when wet snow near the melting point are blown across some sort of non-sticky surface. The wind has to be strong enough to blow the roller into a ball yet not completely dissipate it. These cylindrical snow balls are often hollow due to the fact that the inside layers are not as strong as the outer and can blow away. These usually occur in winter unless you are in a place where it snows all year or sporadically throughout.