I lived in the San Diego County area for more than 30 years and the Santa Ana winds could gust extremely high, but to 100mph? Probably not likely, unless coupled with a fire storm and it's a whole nother ball game. Fires along with the canyons and plenty of dry fuel create their own weather so winds of 100 mph or more is absolutely possible. I lived through a fire storm that swept through Ramona Ca, (The San Diego Country Estates) in the 2000s and can attest to how destructive and deadly high winds and fire can be. I stayed and protected my house because I knew no one else would.Not 100mph.
But Santa Ana winds are normal and typically a fire hazard. Being unprepared makes no sense.