http://www.newsweek.com/sinkholes-could-swallow-chunks-california-after-rain-flooding-1773660

California has been hit by heavy rain and flooding since the end of 2022, resulting in the formation of sinkholes in some locations, and with more wet weather ahead for the state, it's possible more could open up.

Sinkholes are gaping holes that form when the ground below the land surface cannot support the material above. They can vary in size from a few feet to hundreds of feet across, and from a few feet to tens of feet deep.