Swimmers have been warned of the dangers of debris beneath the surface
A warning has been made to people about the dangers of swimming in waterways and lakes during the warm weather following the death of a teenager.
Seventeen-year-old Jack Chapman, from west London, died in Widdop Reservoir near Hebden Bridge on Wednesday.
The teenager had been swimming when his friends lost sight of him.
Yorkshire Ambulance Service said there had been a spate of incidents where people had been seriously injured by being in and around open water.
Jack Ewing, from the Yorkshire Ambulance Service, said: "The county's waterways and lakes are a popular destination for people in hot weather, which can make them a dangerous place for those who take risks.
"It may be very tempting to jump into the water to cool off on a hot summer's day but people need to be aware of how dangerous it really is.
"Water can look calm on the surface but can contain unseen debris and rivers in particular can have treacherous undercurrents.
"Even on a hot day the temperature of the water is much cooler than people expect so the body can go into shock very quickly and this can cause respiratory problems."