In the space of just 48 hours, seven people have drowned in NSW.

The most recent death is that of a 57-year-old Grafton man who drowned while trying to save the lives of two girls at Wooli Beach, on the north coast of NSW.

He had been sitting on the beach with family when he noticed the swimmers, outside the flagged area, in distress. Without hesitation, he entered the water in an attempt to rescue them. It was later discovered they had been caught in a rip.

Paramedics and SLSNSW performed CPR for 50 minutes, but the man died at the scene.

Sad news at Wooli today with a male swimmer unable to be revived despite best efforts of lifeguards. Read more here https://t.co/D5WEvSInSM

— Surf Life Saving NSW (@slsnsw) December 26, 2016

In light of this tragic death, here is what to do if you – or your children – are caught in a rip.

What is a rip?

Rips are the most lethal hazard on Australian beaches.

Beachsafe describes a rip as “strong currents of water flowing away from shore through the surf zone. They are a strong force and on any give day, there are about 17,000 rips at beaches around Australia.”

Image via iStock.

How do I identify one?

Rips aren't always easy to spot, as they are complex and fast moving.

The signs to look for include: a rippled surface surrounded by smooth water, deeper, dark-coloured water; less breaking waves or gaps between the waves; anything that appears to be floating out to sea; and foamy, sandy water being pulled beyond the waves.

How can I best avoid them?

Particularly if you're not a strong swimmer, keep your feet on the sea floor to avoid being caught in a riptide.

Always swim between the flags, and do not swim at an unsupervised beach. If you are concerned, speak to the lifeguards on duty about surf conditions.

Image via iStock.

Stay calm

The most important thing in the event of a rip is to stay calm.

Dr Rob Brander, a surf scientist from the University of New South Wales, says, "There is a myth that rips will pull you under the water, but there is no such thing as an undertow."

This belief can cause people to panic. It's important that in the event of a rip, you conserve energy.

Do not swim against the rip

When people panic, their first instinct is to swim against the rip.

As tempting as that might be, the speed of a rip can reach more than 7km per hour. If you panic, or attempt to swim back to shore, you will likely wear out.

It's best to try floatingwiththe current, as this may bring you back to shore.

Lifeguard with safety rescue swimming bouy watching public swim in ocean waves

Raise your arm

Raise your arm and call for help.

If you're a strong swimmer, swim parallel

Rather than attempt to swim back to shore, Dr Brander advises you swim parallel to the beach.

A rip is rarely more than 30 metres wide, so it is most effective to swim to the side of the rip, and then swim back to shore. If you get tired, just lie on your back and stay afloat.

What if my child is caught in a rip?

Alert the lifeguard immediately. Often, as was the case with the 57-year-old man in NSW, it is the person who attempts to make the rescue that ends up drowning.

If you do enter the water, only do so with a flotation device.