Forecasters warn of 21-foot waves on Lake Michigan, ‘life-threatening’ conditions and the possibility of beach erosion, flooding
A beach hazards statement was made Tuesday morning, warning of the potential for waves between 12 and 16 feet high in portions of northwest Indiana along Lake Michigan — with the potential for occasional waves as high as 21 feet.
A similar warning went into effect at 3 p.m. for waves as high as 18 feet in Cook County, according to the National Weather Service.
Warnings about the high waves, beach erosion and the possibility of lakeshore flooding came as the city had cooled off considerably. Wednesday is the autumnal equinox — which causes a uniquely local event known as Chicagohenge — meaning Mother Nature jumped the gun a bit with temperatures that weren’t expected to get out of the 60s Tuesday. The chilly temps prompted the weather service to use the headline “Autumn arrives tomorrow, autumnal temperatures today” on a weather recap on its website.
“These types of waves, you know, happen a handful of times each year,” said meteorologist Lee Carlaw, with the National Weather Service in Chicago. “In fact, this is the time of year for it as we go into the autumn.”
Forecasters warned that the high lake levels, combined with potentially some of the highest waves in months, could result in minor to moderate flooding near the lakeshore.
The warning also said waves were expected to be highest Wednesday into Thursday, when strong, northerly winds will lead to higher and stronger waves. The warning for northwest Indiana covers Lake and Porter counties and extends to Cook County.
“The large waves and rising lake levels will result in inundation of low lying and flood-prone areas near the lake as well as beach erosion,” according to the weather service website.
National Weather Service records for Lake Michigan only go back to 1981, Carlaw said. Since then, the highest recorded waves were in 2011 — at 23 feet high about 40 miles east of Kenosha, Wisconsin.
With north-to-south winds, higher waves likely built as they reached Cook County and northwest Indiana, Carlaw said. But the weather service doesn’t have records going back to 2011 from buoys closer to the shorelines of Chicago and Indiana, he said.
“So, in all likelihood the waves were higher than that,” Carlaw said of the 2011 record. “But that is the kind of highest official reading that we have available to us.”
Although Chicago beaches are closed, there have been multiple drownings recently, including a 21-year-old who died in Evanston this weekend. The city held a news conference Tuesday to remind the public to stay out of the water, as lifeguards are no longer present on beaches in the offseason. Meteorologists said the danger will only be exacerbated in coming days.
“Swimming conditions will be life-threatening, especially for inexperienced swimmers,” it said. “Remain out of the water to avoid dangerous swimming conditions and do not venture out onto piers, jetties, breakwalls, or other shoreline structures.”
Check for more information on the forecast at the Tribune’s weather page.
