A rip current is a relatively small scale current of water flowing away from the beach. Rip currents develop when there is an uneven distribution of water onshore. The uneven distribution can be caused by a variety of conditions, including moderate to high wave heights, longer wave periods (how often the waves come onshore), or very direct wave angles of approach. As winds blow over the lake and generate waves, the waves move towards the beach and crash onto shore. Uneven distributions of water will cause areas of high pressure and areas of low pressure in the water. Fluids flow towards low pressure (in the atmosphere and water). As an example, think of what happens in the bathtub when you open up the drain. The water will flow into the drain (area of low pressure). The same thing happens on the beach, except the water converges and heads OUT towards the lake.
Why Rip Currents are Dangerous
Rip currents are the leading surf hazard for all beachgoers. They are particularly dangerous for weak or non-swimmers. Rip current speeds are typically 1-2 feet per second. However, speeds as high as 8 feet per second have been measured–this is faster than an Olympic swimmer can sprint! Thus, rip currents can sweep even the strongest swimmer out to sea.
Over 100 drownings due to rip currents occur every year in the United States. More than 80% of water rescues on surf beaches are due to rip currents. According to the National Oceanic and Atmospheric Administration’s National Weather Service Office, in 2011, 10 people drowned in rip-current incidents on Lake Michigan, while an additional 60 swimmers were rescued from a life-threatening rip current situation. Among the Great Lakes, Lake Michigan had the largest incidence of rip-current incidents during 2011.
Rip currents can occur at any surf beach with breaking waves, including the Great Lakes. Rip currents can be found on many surf beaches every day. Under most tide and sea conditions the speeds are relatively slow. However, under certain wave, tide, and beach profile conditions the speeds can quickly increase to become dangerous to anyone entering the surf. The strength and speed of a rip current will likely increase as wave height and wave period increase. They are most likely to be dangerous during high surf conditions as the wave height and wave period increase.
Where Rip Currents Form
Rip currents most typically form at low spots or breaks in sandbars, and also near structures such as groins, jetties and piers. Rip currents can be very narrow or extend in widths to hundreds of yards. The seaward pull of rip currents varies: sometimes the rip current ends just beyond the line of breaking waves, but sometimes rip currents continue to push hundreds of yards offshore.
How to Identify Rip Currents
Look for any of these clues:
- a channel of churning, choppy water
- an area having a notable difference in water color
- a line of foam, seaweed, or debris moving steadily seaward
- a break in the incoming wave pattern
None, one, or more of the above clues may indicate the presence of rip currents. Rip currents are often not readily or easily identifiable to the average beachgoer. For your safety, be aware of this major surf zone hazard. Polarized sunglasses make it easier to see the rip current clues provided above.
How to Avoid and Survive Rip Currents
- Learn how to swim!
- Never swim alone.
- Be cautious at all times, especially when swimming at unguarded beaches. If in doubt, don’t go out!
- Whenever possible, swim at a lifeguard protected beach.
- Obey all instructions and orders from lifeguards.
- If caught in a rip current, remain calm to conserve energy and think clearly.
- Don’t fight the current. Swim out of the current in a direction following the shoreline. When out of the current, swim towards shore.
- If you are unable to swim out of the rip current, float or calmly tread water. When out of the current, swim towards shore.
- If you are still unable to reach shore, draw attention to yourself: face the shore, wave your arms, and yell for help.
- If you see someone in trouble, get help from a lifeguard. If a lifeguard is not available, have someone call 9-1-1 . Throw the rip current victim something that floats and yell instructions on how to escape. Remember, many people drown while trying to save someone else from a rip current.
GreendaleWeather.com provides beach conditions for the local area. Follow the link to Area Beach Conditions.
Click on the image above for an informative brochure about Rip Current Safety.
Beach Hazards on the Great Lakes
- High Wave Action
- Rip Currents
- Structural Currents and Longshore Currents
- Outlet Currents
- Channel Currents
Hypothermia on the Great Lakes
- Quick Current Types 101 Reference Sheet
- Beach Safety and the Flag System
- National Weather Service Beach Forecasts and Beach Hazard Statements
- Rip Current Videos: How to ID & Escape Rip Currents [NOAA/USLA]
National Pages, Water Safety Groups, and Educational Resources
- National Rip Current Page (NOAA)
- National Beach Hazards Page (NOAA)
- Great Lakes Surf and Rescue Project
- Sea Grant Dangerous Currents Page
The Great Lakes Current Incident Database:
- The Great lakes Current Incident Database
- Statistics on Great Lakes Current Related Incidents
- Great Lakes Current Incident Database: Seasonal Summaries