What are rip currents?
Great Lakes rip currents are strong, narrow channels of water flowing away from shore. Rip currents are natural phenomena that transport sand and flush surf-zone water. Unlike "undertow" (sub-surface currents) and "riptides" (currents formed by tributaries or another incoming water source), rip currents form on the surface of the water and are created by wind and breaking waves returning to the lake. Rip currents result when water rushes offshore in a narrow channel. These currents can extend up to 1,000 feet, reach 100 feet in width, and travel up to 5 mph. This is slower than you can run, but faster than you or even an Olympic swimmer can swim. They are most prevalent after storms.
When and where do rip currents form?
Rip currents form due to factors like wind, wave activity, shoreline structures, and weather conditions. According to MacMahan et al. (2011), rip currents tend to exist when waves are coming directly toward the beach. They report rip currents most commonly develop on beaches that exhibit alongshore variations in a sandy bottom because waves break more over shallow regions and less frequently over deeper regions. The surf-zone water is pushed onshore by the breaking waves in the shallow areas (known as shoals) andreturns through the deeper rip channels. Great Lakes rip currents typically form at low spots or breaks in sandbars. They can also form at beaches with breaking waves, groynes, jetties, or piers. The sandy beaches along Lake Superior's south shore are susceptible to rip currents.
Why are rip currents dangerous?
Rip currents can pull even the strongest swimmers hundreds of yards away from shore. They average a speed of 0.5 to 1 m/s (roughly 2 feet per second) but their speeds can fluctuate. Although over 100 people die in the U.S. each year because of rip currents, surfers and lifeguards commonly use rip currents to quickly exit the surf zone. MacMahan et al. (2011) suggest, "In our opinion, increased knowledge is the best approach to making a rip current 'foe' into an 'understandable friend.' If you understand how rip currents work, and if you know how to swim and float, you may not be alarmed nor become panicked if you find yourself riding in a rip current."
An Introduction to Rip Currents Based on Field Observations, 2011, by J. MacMahan, A. Reniers, J. Brown, R. Brander, E. Thornton, T. Stanton, J. Brown, and W. Carey, Journal of Coastal Research: Volume 27, Issue 4: iii-vi. doi: http://dx.doi.org/10.2112/JCOASTRES-D-11-00024.1
Surviving the Grip of the Rip
Nationwide, rip currents are responsible for more than 80 percent of lifeguard rescues and claim more than 100 lives each year, more than hurricanes, lightning, floods, and tornadoes. It is important for swimmers and recreationists to know how to identify rip currents and how to escape if caught in one.
To avoid being caught in a rip current, know the signs for spotting the dangerous channels. Some basic signs are:
- A channel of churning, choppy water.
- Different-colored water from stirred sediment.
- A break in the incoming wave pattern.
- Foam, plants, or other objects moving away from shore.
Apart from natural signs, other people have set precautions to make sure the public knows about rip currents. Here are some ways you can utilize these efforts:
- Look for rip current warning flags at your beach. These are visible at some beaches in the Great Lakes region. A green flag means low risk. A yellow flag means moderate risk. And a red flag means high risk.
- Use flotation devices such as boogie boards when swimming.
- Note the location of the nearest lifeguard in case of an emergency.
If caught in a rip current, do not try to swim against the current. Instead, do the following:
- Stay calm. Trying to swim against the current will expend energy and lead to drowning.
- If you know the direction of flow, swim perpendicular to the current until you are free, and then swim toward shore at an angle away from the current.
- If you do not know the direction of flow, float on your back until the rip current dissipates, and then swim back to the shore at an angle away from the current.
- Remember the 3 "F"s of rip current safety: Flip, Float, and Follow. Flip over onto your back. Float to conserve energy and keep your head above water. And follow the current until it dissipates. Then swim to shore at an angle.
- If you feel you will not be able to reach shore alone, face the shore and draw attention to yourself, if possible.
Assisting Rip Current Victims & Recognizing Drowning
To help someone caught in a rip current, first remember that many people have died in efforts to save rip current victims. If you have not had professional life guard training, you can help by doing any of these things:
- Get help from a lifeguard.
- Yell instructions to the victim on how to escape.
- Throw the victim a flotation device to help them stay afloat.
- Call 9-1-1 for assistance.
Remember that drowning rip current victims may not be able to wave or yell. Drowning people cannot yell. Speech is a secondary function of the respiratory system, and the person may be bobbing up and down in the water, struggling for air. They also cannot wave their arms. It is human instinct to keep arms lateral, against the surface of the water, to keep from drowning. In such a situation, it is tough for victims to perform any voluntary actions at all. Keep an eye out for swimmers that seem to be struggling or seem to be too far away from shore.
Rip Currents along Minnesota Point ("Park Point")
Rip currents can form along the shores of the Great Lakes, including Lake Superior. Although these dangerous channels can occur in somewhat unpredictable places, one of the most likely locations on Lake Superior is Minnesota Point ("Park Point"), due to its sandy beach.
Aerial photos of Minnesota Point show that the lake bottom along the shore has many dips and trenches. These low spots may be remnants of past rip currents or pre-formed channels where future rip currents can appear once more.
Rip currents along this stretch have been the cause of many incidents and rescues throughout recent years. Jump to News Stories.
For additional public safety along Minnesota shores, flags are flown at 4 locations along the beach that match the Duluth National Weather Service (NWS) Office's daily surf forecasts for Lake Superior beaches online. The surf forecast categorizes the risk of rip currents for swimmers as low (green flag), medium (yellow flag), or high (red flag), based on wind direction and speed, and wave height. The flags are changed daily to match the risk, and are changed to red if rip currents are spotted.
In 2006, Minnesota Sea Grant surveyed local beach users about their knowledge and awareness of rip currents. See a newsletter story about the findings here.
Know before you go: Starting in 2012, Park Point beach users can access beach conditions online. ParkPointBeach.org has continually-updated beach conditions throughout the day, including rip current risk, beach closings, wind and waves, water temperature, and more.
Twin Ports Rip Current Workgroup
This organization formed after a 2009 rip current workshop in Duluth to coordinate rip current awareness activities in the region. Members include: MN and WI Sea Grant, the City of Duluth Parks and Recreation, Duluth Fire Department, Duluth National Weather Service Office, Duluth YMCA, Northland Red Cross, and Minnesota's Lake Superior Coastal Program. Activities include development of the beach flag system, coordination of an annual water safety expo, and participation in the River Quest program to teach 6th graders about rip current safety.
Rip Currents in the News
- An 8 and 10-year-old brother and sister were carried 500 feet offshore by a rip current on Minnesota Point. Their mother went in after them to find herself trapped as well. First responders took the mother and children to the hospital after other beachgoers rescued and brought them ashore.
- The Duluth News Tribune reported that a boy was caught in a rip current after 1 p.m. but was able to make it ashore unassisted.
- The City of Duluth closed beaches for the 3rd or 4th time due to rip current danger in summer 2007.
- The City of Duluth closed beaches due to rip current danger.
- Around 2 p.m., after the beaches were closed, several people (children and adults) were rescued from rip currents along Minnesota Point. Many stated they didn't know the beaches were closed.
- 14 mph winds were recorded at the National Weather Service station on Miller Trunk Highway.
- A WDIO reporter assisted in a rip current rescue.
- A swimmer was rescued from a rip current by a firefighter near 1600 Minnesota Avenue on Minnesota Point.
- 15 mph winds were recorded at the National Weather Service station on Miller Trunk Highway.
- 4-6 foot waves were reported.
- Several swimmers were rescued in several locations along Minnesota Point, including a stretch near Lafayette Square and 12th Street.
- Matthew Rheaume drowned in a rip current. 14 mph winds were recorded at NWS station on Miller Trunk Highway.
- Download a case study of this event. (840k PDF)
- “Rip Currents Hit Home” article from Seiche newsletter
- Superior Science News Radio Program
- Lake Superior Rip Currents (4:40) - Aired 8/5/08 and 8/7/08
- 4.3 MB mp3 | Stream | Transcript
- Listening to the Lake Radio Program
- Rip Currents (9:09) - Aired 6/1/05
- 10 MB mp3 | Stream | Transcript
Great Lakes Rip Current Conference (2009)
Presentations from the Conference:
- Rip Current Education & Outreach (PDF)
- Gene Clark, PE Coastal Engineering Specialist, U.W. Sea Grant Institute
- Mackinac County Water Safety Review Team: Educating the Public on Rip Currents (PDF)
- Ron Kinnunen, Michigan Sea Grant
- NOAA/NWS Forecasting and Observing of Great Lakes Rip Currents (PDF)
- Dave Guenther, WFO Marquette
- Rip Currents in Lake Superior (PDF)
- Jesse Schomberg, Minnesota Sea Grant
- The Mechanics of Rip Currents in the Great Lakes (PDF)
- G. Meadows, H. Purcell, and L. Meadows, University of Michigan
- Rip Currents: A Survey of Beach Users (PDF)
- Jesse Schomberg, Minnesota Sea Grant
- Surf Zone Forecasts on Western Lake Superior (PDF)
- Dean Packingham, National Weather Service, Duluth, MN
- Littoral Environment Observation Data Collection (PDF)