A sudden downpour late morning on Monday washed across St. Mary’s, hitting the northern area around Mechanicsville and Charlotte Hall the hardest.

Across Southern Maryland, weather service meteorologists observed “2 to 3 inches [fall] in less than an hour,” meteorologist Howard Silverman said.

“That was the time that the strongest shower and thunderstorm activity moved through,” Silverman said. “That extent of rainfall is hard for the ground to absorb, regardless of how saturated or dry the ground is,” he added.

The National Weather Service issued a flood watch for Southern Maryland on Monday morning, effective until 6 p.m. that day for St. Mary’s, southern Prince George’s County and Charles County. A coastal flood warning was put in effect until 11 p.m. Monday.

Local weather watcher John Zyla reported 2.46 inches of rain in Ridge at 4 p.m. Monday. Naval Air Station Patuxent River’s weather station reported 2.92 inches between 8 a.m. and 2 p.m. that day, while spotter reports in Golden Beach saw 4.39 inches of rain recorded at 11:45 a.m. At 4:30 p.m. Monday, weather watchers in California reported 3.64 inches of rainfall, according to data from the National Weather Service.

Several roads were closed in St. Mary’s on Monday after the late-morning deluge. Around 2 p.m., Maryland Department of Transportation State Highway Administration began working to address a minor landslide on New Market Turner Road in Mechanicsville, SHA public information officer Charlie Gischlar said.

“That sounds a lot worse than what we’re responding to,” Gischlar said Monday afternoon. “A bunch of rain had washed out some mud that went into the road, [bringing] other rock debris,” he said.

The St. Mary’s County Department of Public Works dispatched 12 crews during the peak of the storm to mitigate flooding on Mechanicsville Road between Yowaiski Mill Road and Route 234; a location on baptist Church Road; South Sandgates Road at the Patuxent River shoreline; All Faith Road; and Maddox Road, between Hurry Road and Budds Creek Road.

Public works director John Deatrick said that an area of Spruce Drive between Maple Road Hollow Lane, and a portion of Cox Drive between Cox Court and Julia Court will be closed for roughly two weeks due to flooding damage that caused culvert collapses and pavement damage. Those sections of roadway are expected to be closed until July 19 for repairs, according to a release from county government.

Gerald Gardiner Jr., St. Mary’s emergency management manager, said that from 11 a.m. to 3 p.m. emergency services received 12 calls related to the flooding, including “one or two trees down, we had a bunch of high water in the roadways, we had a watercraft that was in distress during the height of the storm.”

Gardiner said the sea vessel “really turned out to be a good intent call” from a concerned observer near North Sandgates Road. The boat was not overturned, and no injuries were reported.

The emergency services RSS feed showed reports of fallen trees on Route 235 in Mechanicsville and on Charlotte Hall Road, and responses to calls about flooding conditions in Mechanicsville and California.

Southern Maryland Electrical Cooperative communications director Tom Dennison said SMECO had received about 82 calls in St. Mary’s regarding power outages scattered across the county before 2 p.m., but reported “no major feeder outages.”

In the D.C. metropolitan area, “We had as much as 6 inches of rain that fell in a short period of time. … Quite a bit of flash flooding,” Silverman said.

Twitter: @TaylorEntNews

Twitter: @TaylorEntNews