Most of the region was forecast to get around an inch (about 2.5 centimeters) of precipitation over several days, but “the threat is high enough to prepare for the worst-case scenario” of localized cloudbursts causing mud and debris to flow down hills,

Rainfall has provided relief to wildfire-stricken Southern California but posed new threats of toxic ash runoff and debris flows. Authorities are expediting cleanup efforts and implementing flood-control measures to mitigate environmental impacts.

Rains have finally arrived in Southern California, aiding firefighting efforts in the region. However, the weather also raises new concerns about potential mudslides and toxic runoff on burn-scarred hillsides.