After a weekend storm walloped San Francisco, officials say preventing flood damage from powerful rains in vulnerable areas of the city largely remains a pipe dream.

A storm that inundated San Francisco with more than an inch of rain in a single hour Saturday flooded two Muni light-rail stations, snarled traffic on Highway 101 and forced residents in parts of West Portal to wade through waist-deep water that surged into homes, causing thousands of dollars of damage.