WITH A FEROCITY beyond the ken of even longtime residents, Tropical Storm Gaston delivered a pounding blow to Richmond and its environs Monday night, killing at least five people, drenching downtown in nearly a foot of surging water, spawning twisters, wrecking scores of city blocks, and leaving at least 100,000 homes and businesses without power or mobility. Meteorologists -- fooled by the storm's erratic movements -- had predicted one to four inches of rain; instead, flooding caused by hard-driving torrents ripped up the landscape and piled cars, sections of buildings, chunks of pavement and assorted debris into mini-mountains.

Despite sophisticated tracking equipment, these storms can and still do defy accurate predictions, and Richmond was caught way off guard. Gov. Mark R. Warner (D) wasted no time declaring a state of emergency for the hardest-hit areas, and he is seeking a federal designation as well. As reported by The Post's Michael D. Shear in Richmond, surveyors began conducting a building-by-building assessment of structural damage yesterday; in some spots, gas leaks prompted fears of explosions. City and state officials said that a 25-block area could be condemned as unlivable: Just east of the state capitol and near the banks of the James River, Shockoe Bottom -- one of the oldest neighborhoods, where tobacco warehouses have been converted into popular dining and entertainment spots with a mix of apartments -- was inundated.

Recovery will be long, painful and costly. Some businesses may never return, and families will suffer severe hardships in their quests to regain their footing. People elsewhere in Virginia and in other areas spared by Gaston already are volunteering help and resources to aid the stricken. The generosity of individual Americans in these emergencies is generally magnificent, which is well: Richmond will need all the goodwill that others can extend.