Crews spent up to six hours Friday clearing bridges and culverts along the Fall River jammed by early morning storms.

The Hot Springs and southern Black Hills area was under a flash flood watch issued by the National Weather Service until midnight Friday. Most of western South Dakota was also under a severe thunderstorm watch through midnight, the weather service said.

The state Department of Corrections sent a team of 20 minimum-security inmates from Rapid City to help remove debris, including 36-inch logs, floating down Fall River and causing flooding over bridges.

Lightning preceded the heavy rainfall that started about 3:30 a.m., striking one storage garage north of Hot Springs and starting one small fire. There were no reports of injuries.

Frank Maynard, Fall River County emergency manager, said he heard reports of at least quarter-size hail about 4 miles south of Hot Springs and more than 2 inches of rain in 20 minutes.

As of early Friday evening, two roads were closed because of water over the bridge: Beaver Road and Dewey Road. In Hot Springs, some streets were closed for cleanup, but Maynard said the water had receded in most areas.

Because it was overflowing its banks in some low-lying areas in Edgemont and from the Wyoming border to Angostura Reservoir, the Cheyenne River is being closely monitored, as well as the streams that flow into it. However, no structures are near the river. Maynard said officials were being especially cautious because additional rain was predicted.