What is "seracs"

Usage examples of "seracs".

The front edge was uneven, accommodating minor local differences in terrain, and a climb to the top would have revealed dips and ridges, seracs, and crevices quite extensive on a human scale, but in relation to its own size, the surface was uniformly level.

The four of us stood there silent for a second, listening to the wind howl around the remaining seracs of the Godwin-Austen Glacier and through niches in the wind-carved boulders.