Swim with Caution

At least four of the drownings that occurred in July 2003 happened on private beaches where shoreline structures are known to be present. Another three drownings took place nearby in the Warren Dunes area. The Michigan Department of Natural Resources had posted red flags, warning swimmers to stay out of the water due to strong longshore currents (about .5 mph) and high winds and waves earlier in the day.

Winds were a significant factor that day, according to Dave Guenther of the NOAA National Weather Service, based in Marquette. He has been studying the drowning cases in southern Lake Michigan and several other events that have occurred over the past few years. According to Guenther, the squall that passed across Lake Michigan on the morning of July 4, 2003 probably created excess water near shore. Even though the waves diminished to one to two feet by afternoon when the drownings occurred, the wind was still shifting.

“As the wind veered northeast, it produced rip channels in the sand bars. When the wind swung to the southwest, it produced a longshore current later in the day that followed the rip channels out to sea,” says Guenther.

Other incidents that Guenther has studied involved four men who drowned in Lake Erie near Huron, Ohio in 2002 and one drowning near Duluth, Minnesota in August 2003 on a day when seven other swimmers were rescued. In the Duluth case, says Guenther, a steady wind blew from the northeast for most of the day. Three- to four-foot waves hit the shoreline head-on, or perpendicular to shore, and set up conditions that produced what appears to be a classic example of a rip current.

“People who were out there that day said they were having a lot of trouble getting back to shore,” he noted.

Guenther is working with colleagues from the National Weather Service to develop a rip current forecasting system and is optimistic about the progress: “Hopefully by next year, we’ll have an advisory program Great Lakes wide.”