We're north of Los Angeles and the area has never really handled rain well. This is also entirely anecdotal having lived here for ~35 years.

Some of the towns in our county have developments built on floodplanes. In our neighborhood, only some streets have storm drains so many of them flood. On one of the main roads numerous trees fell over damaging walls and homes.

That last set of storms that really stands out were the El Niño events in the early oughts.