Fire, flood and mud are what we live with in CA. Trust me, nobody spends a few years here and "forgets" that it's not all sunshine and ocean breezes, LOL. You learn quickly that the reason why the coastal areas are so expensive is that they are (1) hard to build on - CA is mostly shale and sand at the shore, not granite; (2) erosion is constant - you may buy it today but 100 yrs don't be surprised if your heirs find their 1/2 acre site whittled down to one-third that size by ocean currents.
This photo was out of the NY Times archives. It is NOT Montecito, it is a photo of La Conchita, a coastal community just south of Montecito about 17 miles. In 1995 they had a massive mudslide that buried a dozen houses. They erected a massively reinforced wall to the highest standards they could.
In 2005 another mudslide came down. It deflected over the wall and kept coming down. Per the NY Times: "...
Ten people were killed in that January 2005 mudslide. Their bodies were recovered but parts of their homes are still buried under a giant mound of soil, a monument to the town’s suffering and lingering fears."
This is the photo of that 2005 mudslide. As you can see, it's density that's the problem. The town only has 330 residents. But it doesn't take much width in these modern days, to wipe out a dozen homes or more.
The reason flooding after fire is always a concern is that really intense fires can "fuse" the soil surface. It can take up to two years for the soil to recover its natural absorption. On flatlands this is less of a problem - but CA's coast is very craggy and full of chasms.
If you've ever driven from the Washington/Oregon coast down into CA's northern coast, you'll have noticed this. It's not just a change in plant life - the coastal geography becomes noticeably different. "Walking beaches" like Moonstone Beach in Cambria are not the norm here.