Another example of good, relevant reporting by AP https://apnews.com/article/southern-california-debris-flow-rain-wildfire-663334ac70b701eb8e761da5269dd02d

Sounds like the heavy rains (up to 100mm) over the hilly burnt areas in #LAfires did cause the expected mud slides but mud only went up 20cm in the roads - while remaining buildings were protected by sand bags and temporary concrete walls.

With the top soil now washed away, will new plants be able to take root at all? I guess so. Because this mediterranean biome, called Chaparal biome, consists of shallow root grasses, shrubs and low trees. Not like in the Rockies in the article above.
And could the precious mud in the roads now be hauled back uphill ? I guess not. Because it also contains the toxins from all the burnt buildings, I reckon.