mushrump
A mushroom shaped pillar of winter snow capped by a clod of dirt, a dead animal, or a piece of trash, left standing while snow around it melts away. The pillar gradually hollows but the top is the last to melt since it is protected by the detritus. They last but a short time and are a sure sign of Spring in Vermont.  
In common usage in our region.
Combining form of
mushroom and stump perhaps rump
We took a Sunday drive today on the backroads and saw many well formed mushrumps, including one capped by a skunk, priceless.