Fast Facts

• Widespread freezing drizzle developed over Illinois and western and northern Indiana during the afternoon of Saturday, January 8 and continued into the evening, resulting in an impacting glaze of ice.

• This event was set up by two cold days in advance with temperatures well below freezing, and then as drizzle spread over (due to warmer, moist air aloft), it would freeze on contact to untreated surfaces as well as some treated ones.

• This event had been forecast fairly well in advance, with a wintry mix noted in the forecast as early as Tuesday, January 4, and then a Winter Weather Advisory issued for January 8 on the afternoon of January 7. 

NWS Chicago Weather Story issued 3 P.M. Friday, January 7

NWS Chicago Weather Story issued 6:30 A.M. Saturday, January 8

• Numerous auto accidents did still occur, including some on interstates with a couple of those main thoroughfares briefly coming to a standstill.

Ice Totals

The below ice totals are from ASOS freezing rain sensors. These use an apparatus that is measuring ice accretion on a flat plane. This is therefore not representative of ice accumulation on elevated radial surfaces, such as trees and wires. For more on ice measurements and the different means, see this video from NWS Caribou, ME.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
920 AM CST SUN JAN 9 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1200 AM     FREEZING RAIN    DUPAGE AIRPORT          41.91N 88.25W
01/09/2022  M0.24 INCH       DUPAGE             IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    AURORA AIRPORT          41.77N 88.47W
01/09/2022  M0.18 INCH       KANE               IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    MIDWAY AIRPORT          41.78N 87.75W
01/09/2022  M0.18 INCH       COOK               IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    OHARE AIRPORT           41.98N 87.90W
01/09/2022  M0.15 INCH       COOK               IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    PALWAUKEE AIRPORT       42.10N 87.90W
01/09/2022  M0.15 INCH       COOK               IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    VALPARAISO AIRPORT      41.45N 87.00W
01/09/2022  M0.14 INCH       PORTER             IN   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    ROCKFORD AIRPORT        42.20N 89.10W
01/09/2022  M0.10 INCH       WINNEBAGO          IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

1200 AM     FREEZING RAIN    WAUKEGAN AIRPORT        42.42N 87.87W
01/09/2022  M0.08 INCH       LAKE               IL   ASOS

            MEASURED BY THE ASOS FREEZING RAIN SENSOR.

Meteorology

NWS Quad Cities weather balloon data (sounding) from 6 P.M. on the evening of January 8. Drizzle / light rain was developing in the saturated layer between 5,000 and 6,000 ft AGL on this sounding.	NWS Chicago lowest level radar reflectivity at 5:20 P.M. on January 8, showing the blossomed ~10 dBZ indicative of drizzle (freezing at the surface).	NWS Chicago lowest level radar reflectivity at 9:18 P.M. on January 8, showing the continued drizzle signature over the Chicago metro. Many surfaces were still below freezing at this time.

Additional

Links

• Adjacent Areas:  Northwest IL   Central IL     WI    Northern IN    Central IN
• National Snowfall Totals
• Snow Depth Information
• Map of Snowfall Local Storm Reports
• Create Your Own Observed Contoured Snowfall Map
• NWS Chicago Past Events Page