Rescue workers resumed their search Thursday morning for a missing 19-year-old swimmer at Tridelphia Lake, west of Clarksville.

Montgomery County Fire and Rescue officials said in a Twitter message that the swimmer is presumed to have drowned as he was swimming with friends near the boat ramp of Greenbridge Recreation Area.

Rescue workers said they were getting ready to continue their search around 9 a.m. Thursday morning after suspending it Wednesday night as isolated thunderstorms and downpour rains hit the area.

The incident began around 6 p.m. Wednesday when authorities received a call from the friends of a man who they say was missing in the water after he went underwater in a cove. Swimming is not allowed in the area but boating and fishing are allowed.

Authorities searched the shoreline with imaging and sonar technology. About a dozen boats were made available by Howard and Montgomery County fire departments.

Search for missing swimmer (Montgomery County Fire and Rescue)

Julie Zauzmer contributed to this report.

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