There’s nothing more inviting than a wide open beach and a dip in the sea on a summer’s day.

Eastern Daily Press: Danielle Chilvers, 37, of Swaffham, who died Sunday after she went into the sea at Waxham to save her 14-year-old son who got into difficulty in a kayak. Picture: PA/BRITTANY WOODMANDanielle Chilvers, 37, of Swaffham, who died Sunday after she went into the sea at Waxham to save her 14-year-old son who got into difficulty in a kayak. Picture: PA/BRITTANY WOODMAN (Image: PA/BRITTANY WOODMAN)

But tragedy can come on a turn of the tide, as dangers lurk in the calmest of waters.

A 37-year-old mother drowned after she tried to help her son and a friend after they got into difficulty on a kayak off Waxham Beach on Saturday.

Rescuers brought Danielle Chilvers from Swaffham ashore but she was pronounced dead in hospital.

Her death has sparked fresh warnings about the dangers of using inflatables on beaches, where children can be carried out to sea. The RNLI says they should only be used on enclosed pools.

Eastern Daily Press: Kristers Bednarskis, who drowned in a lake at Bawsey Pits, near KIng's Lynn Picture: Ilja JevtusenkoKristers Bednarskis, who drowned in a lake at Bawsey Pits, near KIng's Lynn Picture: Ilja Jevtusenko (Image: Ian Burt Photography/GoFundMe)

The previous day, a 22-year-old man drowned after getting into difficulties in a lake at Bawsey Country Park, near King’s Lynn.

Firefighters recovered the body of Kristers Bednarskis, from Peterborough, after searching the water using boats.

No swimming or paddling is permitted at the park, but visitors flout the rules in warm weather.

The RNLI is urging sunseekers to respect the water. Getting away from the crowds may sound idyllic but the RNLI is urging beach-goers to choose spots where lifeguards patrol.

Eastern Daily Press: The RNLI urges families to visit beaches which have lifeguard patrols Picture: Nick ButcherThe RNLI urges families to visit beaches which have lifeguard patrols Picture: Nick Butcher (Image: ©archant2016)

They include Cromer, East Runton, Gorleston, Great Yarmouth, Hemsby, Mundesley, Sea Palling, Sheringham, Wells and West Runton. Details of all beaches with lifeguards can he found here.

When arriving at the beach, the RNLI says you should check warning flags. A red flag means do not enter the water, a red and yellow flag means lifeguards patrolling, while a black and white flag means a launch area for kitesurfers, windsurfers and kayaks where you should not swim.

Rip tides are strong currents which can drag swimmers out to sea. The RNLI says: “Rip currents can be difficult to spot, but are sometimes identified by a channel of churning, choppy water on the sea’s surface.

“The best way to avoid rips is to choose a lifeguarded beach and always swim between the red and yellow flags, which have been marked based on where is safer to swim in the current conditions. This also helps you to be spotted more easily, should something go wrong.”

Eastern Daily Press: RNLI Lifeguard flags and rescue board on Cromer Beach.Picture: MARK BULLIMORERNLI Lifeguard flags and rescue board on Cromer Beach.Picture: MARK BULLIMORE (Image: Archant Norfolk 2015)

The RNLI says if caught in a rip, you should try to stand because you will not be able to swim against it. It you can not, you should swim parallel to the shore until free of the rip and then head for shore and always raise your hand and shout for help.

Each summer, Norfolk’s lifeboats are called out to rescue people who have been cut off by the tide at Scolt Head and Brancaster.

Tide heights and times change daily, so it is common sense to check before venturing out.

On some beaches, gullies can fill with water a the tide comes in, cutting off people who have walked further out on the shoreline.

Eastern Daily Press: How a rip current happens. Image: ArchantHow a rip current happens. Image: Archant (Image: Archant)

You can find out more information about tides in your area through tide tables, apps, weather news or local websites.

You can also get local tidal information from a harbour master, tourist information centre and some seaside shops.

The RNLI says swimmers should err on the side of caution when it comes to swimming or paddling in breaking waves. If the water is rough, don’t go in.

Swimmers everywhere should be aware of cold water shock. Anything below 15C is defined as cold water and can seriously affect your breathing and movement, so the risk is significant most of the year.

Average UK and Ireland sea temperatures are just 12C. Rivers and inland waters such as gravel pits and broads are often colder.

Cold water shock causes the blood vessels in the skin to close, which increases the resistance of blood flow. Heart rate is also increased. As a result the heart has to work harder and your blood pressure goes up. Cold water shock can therefore cause heart attacks, even in the relatively young and healthy.

The sudden cooling of the skin by cold water also causes an involuntary gasp for breath. Breathing rates can change uncontrollably, sometimes increasing as much as tenfold. All these responses contribute to a feeling of panic, increasing the chance of inhaling water directly into the lungs.

The RNLI says anyone who falls into water unexpectedly should not try to swim straight away. The initial effects of cold water pass in less than a minute. You should relax and float on your back to catch your breath. Try to get hold of something that will help you float.

Keep calm then call for help or swim for safety if you’re able.

If you see anyone in trouble, alert the lifeguards or call 999 or 112 and ask for the coastguard. For ore on safety, go to www.rnli.org.