Bay Area Storm: Up Close and Personal With a Mission District Flash Flood

Here's what happens when a mega-downpour hits the lower-lying parts of San Francisco:

Storm drains or catchment basins get clogged. Stormwater fills the sewers. And pretty soon you have inundated streets and water trying to get into local homes and businesses.

I saw a demonstration of that phenomenon in action coming in to work this morning when I got to the intersection of Harrison and 14th streets, in the northeast corner of the Mission, about 7:30 this morning.

Cars were rolling through a good half-foot of water. What's the big deal? It's rain, right?

Ask Kathy Stillman, at her upholstery shop a few steps from the intersection.

Stillman had water coming in. A neighboring business called the Fire Department. Engine 29 showed up with a squad to clear things up. Firefighter Kevin Tom said he'd already cleared two other intersections.

"It's just the whole system. If you see any manhole covers, you have water just coming out of them. The whole system is just overwhelmed."

Tom says it's not surprising in a storm like this to see standing water in some of the city's low-lying areas -- many of which were wetlands before the city was built up in the 19th century.