A beach hazards statement took effect at 10 a.m. Tuesday, warning of the potential for waves between 12 and 16 feet high in portions of northwest Indiana along Lake Michigan. A similar warning will go into effect at 3 p.m. for waves as high as 14 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.

       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.

       It also said waves were expected to be highest Wednesday into Thursday, when strong, northerly winds will lead to higher and stronger waves.

       “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.

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       Although Chicago beaches are closed, there have been multiple drownings recently, including a 21-year-old who died in Evanston this weekend. The city was expected to hold a news conference 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 back for updates and for more information on the forecast, visit the Tribune’s weather page.

       kdouglas@chicagotribune.com

       Twitter @312BreakingNews

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