In summer of 2003, a 21-year-old man was swimming with friends on Lake Superior's Park Point when he was caught by a rip current. He struggled to swim straight back to shore but became instead one of the more than 100 people in the United States who die each year from their encounter with rip currents.
Rip currents are sometimes called rip tides but their cause has little to do with tides. Rip currents are also sometimes called undertows, but an undertow pulls the swimmer under, not along with the flow of the current.
A rip current situation begins with high winds which push large waves to shore. These waves carry sediments from the lake or ocean bottom toward land and deposit them as a sandbar lying just offshore. When the sandbar builds up enough, water becomes trapped between the land on shore and the underwater sandbar. In time the trapped water finds the weakest section of the sandbar and breaks through. The collected waters rush back through the narrow space formed at a rate of one to eight feet per second or five miles per hour. This can carry even a strong swimmer against their will away from shore.
In some rip current situations in the past few years on Lake Superior, the winds have been recorded as being in the 14 mile per hour range. Rip currents also occur after storms and around man-made structures like breakwaters and docks which jut out into the water. For that reason, swimmers are advised not to swim within 100 feet of man-made structures when conditions are right for rip currents.
Signs to look for before entering the water:
1. Sections of water that seem dirtier than the surrounding water. The sand and sediment from the bottom is being churned up by the swift current.
2. Waves that are bigger and rougher than the surrounding waves.
3. A section of water that appears at a little lower level than the surrounding waters. This is because the water is cutting through the sandbar, creating a channel.
4. If there is foam or debris on the water like twigs moving away from shore at an even rate.
5. Water that seems colder than the surrounding water.
If you are caught in a rip current, do not fight to get back to shore. Do not panic. Instead, swim parallel to the shore until you no longer feel the pull of the current. Even if you are a very strong swimmer, do not try to swim straight back to shore against the current.
If you are not a strong swimmer, the best thing you can do is to float with the current until you do not feel its pull. This may, however, carry you pretty far out. In either case, once you have been released from the pull of the rip current swim at a diagonal back to shore away from the current. Rip currents are usually not more than thirty feet wide, so there is a good likelihood that you can use one of these methods and get out of the current's pull. Remember most of all not to panic.
In several places known for rip currents, swimmers may see signs posted warning of the danger. Many National Weather Service offices will broadcast rip current warnings in a Surf Zone Forecast. In Duluth, Minnesota, the Park Point beaches were closed when rip current conditions were right. Even then, some people did not hear, or perhaps did not heed, the warnings that were broadcast and had to be rescued in the years since the summer of 2003 and that tragic death.