June 2007
Rip Currents in the Great Lakes
Michigan’s Great Lakes beaches attract countless visitors every year. To ensure that these visits are safe and enjoyable, Michigan Sea Grant reminds swimmers to be aware that rip currents can occur at any beach with breaking waves, including the Great Lakes.
Rip currents are powerful, channeled currents of water flowing away from shore. They typically extend from the shoreline, through the surf zone, and past the line of breaking waves.
Lower than average Great Lakes water levels this summer mean swimmers should be alert to changes in nearshore water conditions, says Michigan Sea Grant extension educator Ron Kinnunen, who is also a member of the Mackinac County Water Safety Review Team .
“Because water is farther out, some beaches will have steeper slopes,” explains Kinnunen. “Swimmers should be aware of any changes in water conditions such as a break in the incoming wave pattern, or a channel of choppy water, that might indicate the presence of a rip current.”
Rip currents are caused when water builds up near shore, often after a storm, then rushes lakeward through a break in a sandbar. Rip currents are also common near river mouths and shoreline obstructions such as piers.
Dave Guenther of the National Weather Service in Marquette also warns that rip currents could potentially occur more frequently during low lake levels because there is less clearance above sand bars. As water flows lakeward, it’s more likely to cut channels.
The National Weather Service will continue to include rip current forecasts in its hazardous weather outlooks this summer when the risk of rip currents is moderate or high.
In Michigan, rip currents have been known to occur along the northern Lake Michigan shoreline near US-2, and along the southern and mid Lake Michigan shoreline from the Indiana border north to Traverse City. They also occur along the open beaches on the south shore of Lake Superior.
Michigan Sea Grant distributes informational brochures about rip currents and has coordinated the production and distribution of rip current beach signs, now posted at more than 50 locations. The signs, in English and Spanish, warn swimmers to use caution and describe what to do if caught in a rip current.
By Joyce Daniels
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