Most of the area’s heaviest rain had departed by Saturday, but many apparent effects remained, including the partial collapse of an apartment house, eroded beaches, closed roads, falling trees and soaked bedding for dogs at a shelter.

Nearly a dozen people were displaced from an apartment building in the 3800 block of V Street SE after a basement wall collapsed about 3 a.m., the D.C. fire department said. A building inspector declared the structure unsafe, the fire department said.

The Humane Rescue Alliance, the city’s animal shelter, appealed for help, saying it was in urgent need of towels, sheets and blankets, after Friday’s rains caused flooding in the dog dens at its adoption center at 1201 New York Ave. NE.

Later, the alliance said many people had contributed and it was “overwhelmed by the outpouring of support.”

About 20 roads remained closed in Montgomery County early Saturday, and waterlogged soil around the region caused trees to topple.

In one incident, a CSX freight train struck a tree on tracks in Silver Spring early Saturday.

A small fire broke out in the lead car, but no injuries were reported, the county fire and rescue service said.

As much as seven inches of rain was reported Friday and Saturday.