One southwest Chicago suburb recorded rainfall so heavy this week, it typically happens just once every 50 years, according to the National Weather Service.
Much of Chicago recorded a month’s worth of rainfall in 24 hours this week, with combined rain events Monday night and Tuesday afternoon totaling 3-5 inches of rain across central Cook County. Rain rates just northeast of Mokena were so torrential, they only have a 2% chance of occurring in a given year, according to National Weather Service Senior Service Hydrologist Scott Lincoln.
This is commonly referred to as a 1-in-50 year rainfall event, but there is no guarantee another 50 years will pass before it is observed again. This week’s rain follows even more rare 1,000-year and 500-year rain events observed in Cook County earlier this summer…