Dangerous rip currents cause an average 71 deaths in the US each year. Here's what to do if you get caught in one.

• Rip currents pull people out to sea and can move faster than Olympic swimmers in the water.
• Trying to swim toward the beach against the rip current can quickly exhaust you.

Moving at speeds of more than 5 miles per hour, rip currents are fast-moving channels of water that can pull even strong swimmers away from the shore. Though they don't drag swimmers underwater, the currents can make it difficult to get back to shore, causing exhaustion and panic that leads to drowning.

Over the past decade in the US, there were, on average, 71 deaths per year due to rip currents, according to the National Weather Service. This year, 11 people died over the course of two weeks due to rip currents along the Gulf Coast, CNN reports.

You don't have to avoid the water altogether to stay safe from rip currents. Before getting in the water, check your local beach forecast for rip current risks, and always look for red or yellow warning flags or posted signs. Also, beaches with lifeguards are much safer.

Here's some more advice on how to spot rip currents and swim out if you're caught in one.

What is a rip current?

Rip currents are often mislabeled as rip tides, but unlike tides, they aren't solely caused by the gravitational forces of the moon and sun.

Sometimes when waves spread along a beach, water becomes trapped between an underwater object, like a sandbar, then forms into a river-like channel that flows away from the shore, according to the National Weather Service.

They often form at breaks in sandbars and near jetties, piers, and other structures. The National Oceanic and Atmospheric Association recommends staying 100 feet from these structures when swimming.

Any surf beach, including those belonging to the Great Lakes, can have rip currents. Their length and width can vary a great deal. Usually, they'll range from 50-100 feet wide and stretch to 300 feet long, offshore, or more, according to NOAA.

How to spot a rip current

It can be difficult to see a rip current, especially if it's wide. They may be more visible from higher up, including from a lifeguard station.

Some rip currents look like a swath of darker, calm water perpendicular to the shore between breaking waves. But it may also look choppy. Sometimes seaweed, sea foam, or debris is visible, moving out to sea away from the shore.

It's a misconception that rip currents only form during bad weather. They're sometimes seen after storms on sunny days. Even if the waves are only two or three feet high, there may be rip currents present.

How to get out of a rip current

Whether you're caught in a strong rip current that's pulling from shore, or a weak one that's not necessarily sweeping you out to sea but preventing you from reaching the shore, the United States Lifesaving Association offers the following advice for surviving a rip current:

• Don't panic.
• Don't try to swim toward the shore, against the current.
• Try to swim out of the current by going along the shoreline or toward breaking waves until you don't feel like you're being pulled by the current. Then swim at an angle, away from the current, toward the beach.
• Yell and wave for help if you aren't able to swim out of the current by yourself.

There is research indicating that some rip currents follow a circular pattern, going out and then traveling back toward the beach. That's led some researchers to argue that it may be safer to try to float with the current instead of struggling against it.

However, this advice is controversial and not always effective, according to Outside Magazine. But treading water while assessing the situation may help if you're feeling tired.

If you see someone else caught in a rip current, alert a lifeguard or call emergency services. Try to communicate with the swimmer to follow the shoreline and move out of the current. You can try to throw a flotation device to the swimmer.

Keep in mind that if you try to save someone else and aren't properly trained, you could end up needing rescuing yourself.