The past few days' warm weather has drawn big crowds to Sweden's beaches and lakes and the number of drowning deaths spiked.
On Friday, one person died in a swimming accident in Stockholm and another was found dead in the water in Härnösand in central Sweden.
On Saturday, three people died in accidents in Boden in the north, in Örnsköldsvik in central Sweden, and in Stockholm.
On Sunday night, a boy drowned in the Kisa lake in southeastern Sweden. Another man is suspected to have drowned when swimming in a lake in Värmland in the west.
The fact that all the accidents involve men does not surprise Anders Wernesten.
"Our research shows that men take bigger risks," he said and warned that it is essential to not overestimate one's capacity and to remember that the temperature in Swedish waters is rather low even if the air is warm.
"You underestimate the cold water's effect on the body, it makes you tense", he said.
The number of drowning incidents have increased this year compared to 2012 and Wernesten fears that the trend will continue with a warm summer.