After the death of one of four swimmers critically injured in Minneapolis water emergencies this week, authorities warned swimmers and boaters to be extra cautious this weekend.

City beaches have far fewer lifeguards than usual because of COVID-19 cutbacks, Hennepin County Sheriff David Hutchinson said in a news release Friday.

On Tuesday, two men were pulled from the water at Bde Maka Ska's Thomas Beach by Minneapolis firefighters. Both were taken to HCMC, where one man later died. The second was treated and released.

On Friday, the name of the swimmer who died was released by the Hennepin County Medical Examiner's Office. Mickenzie Tyler Martin, 19, of Santa Clara, Calif., died of freshwater drowning Wednesday night, the medical examiner said.

Also Tuesday, a man was pulled from Lake Nokomis by bystanders who administered CPR. He was taken to HCMC, where he remained in stable but critical condition Friday.

On Wednesday, a woman was pulled from the water at Minnehaha Falls and taken to HCMC, where she too was in stable but critical condition Friday.

"We understand the desire to get out on the water during the summer months, but it is critical for people to understand that due to the COVID-19 pandemic, most beaches are not staffed by professional lifeguards," Hutchinson said. "We urge everyone to study basic water safety techniques, especially those who are not strong swimmers or have not had formal swimming training."

On Thursday, the Minneapolis Park Board, which this spring had announced that there would be no lifeguard service this summer, said that the city's three most-visited beaches will be staffed with lifeguards from noon to 7 p.m. on weekends, starting Saturday. Bde Maka Ska Thomas Beach, Lake Nokomis Main Beach and Wirth Lake Beach will have weekend lifeguards.

In addition, the Park Board said it plans to hire more lifeguards and to have them on duty from noon to 7 p.m. by July 2 at the city's five most popular beaches — the three mentioned above, plus Cedar Lake East Beach and Lake Harriet North Beach.

If the temperature is 85 degrees or higher at 6 p.m., those lifeguard hours will be extended to 8 p.m., the Park Board said.

The city has seven other beaches that will not be staffed by lifeguards this summer.

The Hennepin County medical examiner also Friday released the name of a 43-year-old Shakopee man who drowned Monday in Upper Prior Lake. He was Kevin Charles Webb. The Scott County Sheriff's Office is investigating.