At approximately 9 a.m. this morning, the National Weather Service (NWS) extended a Lakeshore Flood Advisory and Beach Hazard for the shorelines of Cook and Lake County. Originally issued yesterday afternoon, the Flood Advisory will remain in effect until 4 o’clock tomorrow, and the Beach Hazard will go into the evening.
Besides describing portions of the Chicago Bike Path as “typical flood prone locations,” the NWS warns that, “onlookers may be swept into the lake by the large waves.” Other effects include shoreline erosion, strong rip currents, and five-to-eight-foot waves.
The National Weather Service has extended the Lakeshore Flood Advisory for Chicago, in effect until 4pm, Thurs, 9/10. High wave action (6-9ft) will cause lake shore flooding and dangerous swimming conditions. Strong rip currents and structural currents expected. #BeSafeChicago— Chicago OEMC (@ChicagoOEMC) September 9, 2020
A hazardous pattern
Although 2020 is not on target to become Chicago's wettest year on record, it suggests a hazardous and ongoing longterm pattern.
According to the NWS Climatology Report for Chicago, the city averages 3.26 inches of rain and snow per month from January to August. So far this year, Chicago has recorded about 3.73 inches of precipitation per month, 14% higher than normal.
In May, record levels of rainfall caused flash flooding throughout Greater Chicago and also flooded parts of the Riverwalk and Lower Wacker Dr. In August of 2019, the Chicago Tribune reported that high water levels in Lake Michigan had "swallowed up 2 beaches" and "swiped fishermen from piers."
If weather continues at this rate, total rain and snowfall for 2020 will reach 44.76 inches, making it the 11th wettest year on record since the NWS began tracking the statistics in 1871.
The average annual precipitation for Chicago is about 39 inches. The total amounts received in each of the past two years are nearly 30% higher and rank among the top ten wettest months ever recorded. In 2019, 49.54 inches fell, making it the third wettest month on record. In 2018, 49.23 inches were recorded, making it the fifth.
Three of the other top-ten months were recorded in the 2000s, meaning that Chicago has endured half of its ten wettest months on record over the past twenty years.