IPA: /ˈrɒk.fɔːl/
KK: /ˈrɑkˌfɔl/
A situation where rocks fall from a high place, often due to gravity or erosion.
The hikers were warned about the possibility of a rockfall in the area.
Rockfall → It is formed from "rock" (from Old English "rocc", meaning a solid mineral material) and "fall" (from Old English "feallan", meaning to drop or descend). The word "rockfall" describes the event of rocks dropping or descending, typically from a cliff or steep slope.
Picture rocks 'dropping' ('fall') from a solid 'mineral material' ('rock') — that's what a rockfall is.
No commonly confused words.