Winter storm occurrences ... and a hint to the theme of this puzzle

Usage examples of snowdrifts.

Where there were no snowdrifts, the ground was hard and rough, and often slick.

A search was mounted, of course, but he had gone, evidently through the snowdrifts, to make contact with one of the organizations prepared to help ex-Nazis escape.

Gina waded through the snowdrifts a few steps ahead of him, less accustomed to the cold than he was, probably feeling it even more sharply.

There lay only a narrow clearing round the house now, hummocked with unbroken snowdrifts, before the trees began, with a narrow path leading away.