A woman died and a man is in critical condition after they attempted to rescue their dog from the sea.Police were called to Fleetwood Beach in Thornton Cleveleys, Lancashire, at 8.30pm on Saturday following reports that two people were having trouble in the water.Emergency services treated the two people, both in their sixties, after they were recovered from the water by HM Coastguard.A spokesperson for Lancashire Police said: “At this time, we understand that a man and a woman had got into difficulty in the water after entering to rescue their dog who had become stuck.”The woman was pronounced dead in hospital and the man remains in critical condition, Lancashire Police said, adding the dog was recovered safe and well. Multiple people died in the water during the recent heatwave (PA)Officers are now working to identify the woman’s relatives. The spokesperson added: “They were treated at the scene, but sadly the woman, aged in her sixties, was pronounced dead at hospital. Enquiries to identify her next of kin are ongoing.”“There are no suspicious circumstances surrounding the woman’s death, and a file will be passed to the coroner in due course.”At least 13 people, including children, died in water-related incidents during the record-breaking heatwave. The Royal Life Saving Society has urged people to “stop and think” before getting into the water in response to the deaths.It said “warmer weather unfortunately correlates to an increase in accidental drownings” and that despite warmer air, “water temperatures remain very cold”.An urgent search operation is currently underway for an 11-year-old boy who went missing after entering a river in South Yorkshire on Saturday.Police were called to Ferry Boat Lane in Mexborough at 7.59pm after the boy was seen entering the River Don, but was not seen getting out.