AS the mercury rises, people in Calderdale are being warned not to put their lives at risk by cooling off in a reservoir.
Yorkshire Water is urging swimmers to stay safe by staying out of the water this summer.
Reservoirs are extremely dangerous to take a dip in - because the water is so deep and still, their temperature rarely rises above 12C. There may also be strong under-currents as water is sucked into the supply network.
Geoff Lomas, of Yorkshire Water, said: “What began as a day out in the sunshine can turn to tragedy within minutes if you decide to take a dip. It really doesn’t matter how well you can swim - it’s the cold which can kill you.
“As soon as your body feels the shock of cold water, its natural defences kick in. The first sign of trouble is hyperventilation but, if the swimmer stays in the water, the body will gradually shut down to protect the vital organs and muscles will go into cramp.
“The victim will be unable to remain afloat and will sink below the surface and, if help doesn’t arrive within seconds, they will drown.”
For more information on reservoir safety, visit www.yorkshirewater.com/safety