Flash Flood, Cook
- When
- August 30, 9:45 PM CST to 11:50 PM CST
- Where
- Cook County, North Portion
- Reported by
- LAW ENFORCEMENT
- Coordinates
- 41.895, -87.646 (the zone’s center; the record gives no point)
Flash Flood in Illinois, August 30, 2001
Thunderstorms developed over northern Illinois during the evening hours of Thursday, August 30th. A series of thunderstorms moved across northern Cook county dumping torrential amounts of rainfall.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
What happened
The episode as NWS LOT wrote it up.
Thunderstorms developed over northern Illinois during the evening hours of Thursday, August 30th. A series of thunderstorms moved across northern Cook county dumping torrential amounts of rainfall. Chicago Ohare Airport received 4.31 inches of rain, most of which fell between 9 pm and 11 pm. This rainfall brought the total for the month of August 2001 to 12.25 inches, making this the second wettest month on record for Chicago.Flooding was reported on the Kennedy expressway at Cumberland in Park Ridge, the intersection of River and Lee roads in Des Plaines, Industrial Park in Elk Grove, and portions of the Edens expressway. The 93 mile deep tunnel was filled to capacity with 1.6 billion gallons of water by midnight, forcing the Wilmette locks to be opened to dump 75 million gallons of storm and sewer water directly into Lake Michigan. There was one indirect death blamed on the heavy rain. A motorist who said her vision was impaired by pounding rain, struck and killed a 23 year old man.
What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before the first event at Aug 30, 2:30 PM CST, 7 hours 15 minutes earlier.
Area forecast discussion, Aug 30, 2:30 PM CST, 7 hours 15 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 330 PM CDT THU AUG 30 2001 MUST APLOGIZE FOR TARDINESS OF AFD. GOT A LITTLE BEHIND DUE TO EARLIER WARNING SITN BUT JUST ABT CAUGHT UP NOW. ZFP ALREADY SENT. MAIN CHG TO FCST WAS TO LOWER POPS FOR TONIGHT. CURRENT MESO ANALYSES CONTINUE TO SHOW INSTABILITY AXIS WELL TO S OF AREA. TSTMS HAVE BECOME WELL ORGANIZED ACROSS SRN IA AND NRN MO ACROSS WW703 AREA AND OTHER CLUSTER HAS MOVED INTO WRN IN. WITH THIS ACTIVITITY TAKING PLACE WILL BE HARD TO GET MUCH GOING UPSTREAM OF CHI/RFD NXT FEW HRS. DYNAMICS ASSD WITH APCHG COLD FRONT NOT TOO IMPRESSIVE WITH PROFILER WINDS SHOWING POOR SUPPORT FOR TSTMS PROBABLY DUE TO PASSAGE OF WEAK LO LVL TROF THIS MRNG. HOWEVER...PRE FRONTAL AMS IS SHOWING SIGNS OF RECOVERY IN PROFILER WIND FIELDS AND LO LVL DEWPOINTS ARE SUPPORINT SBCAPES AOA 2000 J/KG...SO SOME POTENTIAL DOES EXIECT FOR SCT TSTM DEVELOPMENT YET THIS EVENING...THERFORE WILL CONTINUE MENTION BUT WITH ONLY A 30 PCT POP. FROPA EXPECTD AROUND MIDNIGHT...THEN CONTINENTAL HIGH PRES BUILDS IN OVER UPR GRTLKS SETTING THE STAGE FOR BEAUTIFUL HOLIDAY WEEKEND. AM FAVORING FWC MOS TEMPS IN FCST AS AVN LOOKS A BIT TOO COOL ON HIGHS NEXT FEW DAYS BASED ON TRAJECTORY FCSTS AND H85 TEMPS. .CHI...NONE MERZLOCK
The radar
The national radar mosaic for the moment the first event began.
Event by event
1 flash flood. Local standard time, as filed.
What these are
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Hail and Damaging Winds in Virginia, August 30, 2001
- Rip Current in California, August 30, 2001
- Flash Flooding in Texas, August 30, 2001
- Tornadoes and Flash Flooding in Texas, August 30 to 31, 2001
- Flash Flooding and Hail in Maryland, August 30, 2001
- Flash Flood in Texas, August 30, 2001
- Damaging Wind in Michigan, August 30, 2001
- Flash Flood in Texas, August 30, 2001
- Flash Flood in Texas, August 30, 2001
- Damaging Wind in Missouri, August 30, 2001
- Hail and Damaging Winds in Missouri, August 30, 2001
- Flash Flooding in Texas, August 30, 2001
More
Every storm in Illinois in 2001Every state in 2001This day in weather historyWarnings in Illinois, August 2001
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5262728.