Dirtfall

Dirt and rocks cascade from above you. It's like a waterfall of dirt—a dirtfall!—and you cover your head and take a breath, bending forward in hopes of creating an air pocket for yourself. The dirtfall buries you.

Source: wiktionary

She glanced at Charlie and saw that a pair of arms had snaked out of the wall to trap his lower legs. The dirtfall doubled in volume.

Source: wiktionary

The little colony was thriving, having the benefit of water, a nearby supply of wood, an abundance of plants, animals and fish and minimal damage from the dirtfall.

Source: wiktionary

The road curved as it roughened, with some dirtfalls cascading onto the road in some places from rain and wind.

Source: wiktionary