TRAVERSE CITY — People fanned out across Grand Traverse Bay’s beaches for the last several weeks, but few dared dip more than a toe in the water.
Lake Michigan water temperatures remain lower than usual after one of the coldest winters in recorded history. In the last week, Grand Traverse Bay surface temperatures reached the high 40s and low 50s, compared to the same time last year, when temperatures were in the low- to mid-50s, according to data collected by the Inland Seas Education Association.
“The ice cover over the winter prevented sunlight from penetrating into the surface water,” said Emily Shaw, the association’s education and volunteer coordinator. “Right now, the surface temperature and water temperature are relatively close. As the surface gets more sunlight, it’ll warm up.”
That warm water becomes less dense and stays close to the surface, while the cold water remains below.
Surface water temperatures across Lake Michigan were below the long-term average for most of the year thus far but started closing the gap in June. The water could warm to average levels depending on the summer weather.
“If it’s a normal-to-cold summer, those temperatures could linger,” said George Leshkevich, a physical scientist at the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory. “On the other hand, if it turns around then surface temperatures can warm quite quickly.”
The water temperature could seem unusually cold because it was far above the long-term average in 2011 and 2012, Leshkevich said.
The cold water can be more than just unpleasant; it can be dangerous and lead to conditions like hypothermia and dry drowning.
Dave Benjamin, an executive director for the Great Lakes Surf Rescue Project, said low water temperatures can impair swimming ability.
“About now, it’s unsafe for any period of time, especially if you’re entering water over your head,” Benjamin said.
Benjamin said the shock of cold water can lead swimmers to hyperventilate and drown. It can also cause hypothermia, or a low body temperature that can cause internal processes to slow.
Benjamin recommends people who fall into cold water float on their back and try to control their breathing.
The best thing for beach-goers is to dry off between dips, said Ryan Titcombe, a Grand Rapids-based American Red Cross instructor.
“We would want to avoid the perpetual state of being wet because that’s when hypothermia can be activated more quickly,” Titcombe said.