Authorities have issued a warning to people not to climb on rooftops or jump into rivers as the weather remains warm.
A joint statement from Boston Borough Council and Lincolnshire Poice said that ’the potential for tragedy in both locations is obvious – death or serious injury from falling or drowning’.
It follows youngsters being spotted on rooftops in Boston.
Boston’s Community Inspector Insp Andy Morrice said: “I can understand youngsters during the long summer break wanting to find somewhere to chill with their friends – I was young myself once! But rooftops are not the right places for several reasons.
“For one they may be trespassing and could be in trouble if inadvertently damage was caused. But I am much more concerned about the potential risk they place themselves in.
“It need only a moment’s inattention, a second of play acting, and the consequences can be dreadful.”
The warning reminds people that, despite prolonged periods of hot weather, rivers, drains, ponds, lakes and open water seldom get warm in this country.
The effects of immersion in cold water can overcome even the fittest and strongest of swimmers.
Cold water can quickly saps stamina and strength and if a swimmer is a long way out from the bank they can quickly be in serious difficulty.
Drowning is the third most common cause of accidental death among the under-16s.
Objects under the water which may be unseen from the riverbank can entrap or injure swimmers.
Boston Borough Council’s Community Safety Manager Peter Hunn said: “I don’t want to be a killjoy, but every year people die in open water because they have gone in unprepared for the dangers they face.
“There are a host of hidden dangers which could end in tragedy. If it’s hot and you want to cool off, go to a swimming pool where it’s safe.”
Further warnings regarded boatsm, which regularly manoeuvre in the Grand Sluice and Anton’s Gowt area.
The statement from the authorities said there was ‘a real danger of becoming entangled in propellers or even being caught in the wash of a boat and dragged under by the displacement of the water created by the boats’ movement’.
This can be particularly true in the area by the lock gates which operate on an automated system.
No warning is given prior to the gates operating and anyone swimming in this area when this process is commencing could be drawn through the gates and washed down river.
Other health hazards are include ecoli, Weils Disease and even asthma and eczema.
Swimming is also prohibited in these area and those caught may be liable to a £100 fine.