Authorities say an Oklahoma City woman apparently drowned after taking cover in an underground storm shelter that later flooded.

Oklahoma City police Sergeant Gary Knight says the 42-year-old woman's body was discovered Thursday morning in an underground shelter. She is the only person known to have died in the strong storms that raked the Plains Wednesday and early Thursday.

A meteorologist with the National Weather Service Storm Prediction Center says 6 to 9 inches of rain fell across the Oklahoma City area over the past two days. He says 51 tornadoes were reported as storms hit Nebraska, Kansas, Oklahoma and North Texas.

Forecasters predict severe weather across the region through Saturday.