Flash flooding from a storm that swept through the region Wednesday shut down highways and interrupted MetroLink service, stranding commuters in high water and traffic gridlock during the evening rush.

The flash flooding prompted the American Red Cross to open an emergency shelter at Normandy High School to help residents of north St. Louis County whose homes were inundated. A couple dozen people whose homes were at least temporarily unsafe sought refuge at the shelter at 6701 St. Charles Rock Road in Wellston late Wednesday.

Lightning strikes also damaged several buildings across the area, including an unused corner of the City Museum in St. Louis.

The Metropolitan Sewer District said it would have crews working around the clock to respond to basement backups and street flooding.

Despite the problems, police in Illinois and Missouri reported only a few minor injuries and accidents related to the storms.

In East St. Louis, a dozen motorists needed to wade out of 5-foot-deep water on Interstate 55/70 near Exchange Avenue after their cars became submerged in the downpour.

Several stranded people needed the help of police and emergency workers, including one woman who was carried on the back of an Illinois Department of Transportation employee, but no one was hurt.

Flooding led to the closure of I-55/70 just east of the Mississippi from about 5:15 to 9:15 p.m., leading to traffic jams on the Poplar Street, Eads and Martin Luther King bridges and surface roads as motorists searched for alternate routes.

Flooding on both sides of the river hindered motorists trying to cross the McKinley Bridge in between St. Louis and Venice.

The storm arrived about 4 p.m. and dumped 2 to 4 inches of rain in about an hour and a half, the National Weather Service said.

The deluge caused branches, grass and trash to clog the inlet grates, or drains, at a pumping station in East St. Louis, said Jeff Abel, traffic operations engineer with IDOT. IDOT staffers had to use shovels to clear drains.

The deluge forced a shut down of MetroLink service in East St. Louis. High water closed the Fifth and Missouri and the East Riverfront stops, Metro spokeswoman Dianne Williams said.

Metro used shuttle buses to transport riders across the river to St. Louis, but flooding on the highways and roadways near the stations complicated matters.

The Missouri Highway Patrol and St. Louis police reported problems with flooding on Interstate 70 in low areas that prompted closures and detours near Union Boulevard and Goodfellow and Jennings Station roads.