snowbank
Our sled had thudded quietly into a snowbank,...

Does a snowbank mean a large pile of snow along either side of a road, (two banks of snow on a road,) or just a large mass of snow in the road, or a large mass of snow on any parts of a road (in the road or on the side of a road)?

Question

snowbank
Our sled had thudded quietly into a snowbank,...

Does a snowbank mean a large pile of snow along either side of a road, (two banks of snow on a road,) or just a large mass of snow in the road, or a large mass of snow on any parts of a road (in the road or on the side of a road)?

Answer

"snowbank" just means "a mound or slope of snow".  It can be anywhere, not just in, near, or along a road.
FYI, if a snowbank is made by wind, it is often called a "snowdrift".

Answer

Snowbanks would commonly be along a road or sidewalk that had been shoveled.