Flash Flooding in Illinois, July 9, 2002

Name: Flash Flooding in Illinois, July 9, 2002
Start: 2002-07-09T02:00
End: 2002-07-09T03:30
Location: Illinois

July 9, 2002 · NWS LOT · 2 events in 2 counties and zones

Heavy rain fell over DuPage and Kane counties during the early morning hours of July 9th. Street and basement flooding was reported in Wheaton and West Chicago in Dupage county.

Where it happened

Every event with a place to put it; 2 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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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.

Heavy rain fell over DuPage and Kane counties during the early morning hours of July 9th. Street and basement flooding was reported in Wheaton and West Chicago in Dupage county. Wheaton reported 2.92 inches of rain. Street and basement flooding was also reported in Geneva and Batavia in Kane county. Some retention ponds also filled in Kane county. Batavia reported 5.60 inches of rain and Geneva reported 4.16 inches.

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 Jul 9, 1:57 AM CST, 3 minutes earlier.

Area forecast discussion, Jul 9, 1:57 AM CST, 3 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
257 AM CDT TUE JUL 9 2002

SYNOPSIS...SLOW MOVING COOL FRONT WILL EASE THROUGH CWA THIS MORNING
WITH DRIER AND COOLER AIR TO BE THE RULE INTO THE WEEKEND. A SLOW
MODERATION IS EXPECTED BY THE WEEKEND BUT NO ADDITIONAL RAIN IS IN
THE OFFING.

DISCUSSION...COMPLEX AND SLOW MOVING SUFRACE TROUGH WORKING THROUGH
CWA DURING PREDAWN HRS. TSTMS HAVE BECOME BETTER ORGANIZED AFTER
MIDNIGHT...ENOUGH TO DROP UP TO 3 INCHES OF RAIN IN CNTRAL PORTIONS
OF CHI METRO WEST TO KANE COUNTY AND PROMPT FFW. PART OF CONCERN IS
URBANIZED NATURE OF AREA.  MOST RAIN IS WELCOME NO MATTER HOW MUCH.

MODELS CONSISTENT IN SHOWING UPPER SUPPORT SHORT WAVES SLIDING BY
TODAY WITH IMPRESSIVE SURFACE ANTICYCLONE IN EXCESS OF 1026MB WORKING
INTO CNTRAL GT LAKES BY THUR PM.  THIS IS QUITE STRONG FOR MID SUMMER
AND WILL MEAN SEVERAL DAYS OF DRY AND COOL WX.

NEXT SHORT WAVE FORECAST TO DIVE THROUGH IOWA ON THURS.  WITH SUCH A
STRONG SURFACE HIGH IN PLACE WITH ATTENDANT DRIER NORTHEAST FLOW
EFFECTS FROM THIS SYS IN NRN ILL WILL BE NIL.  NEW MRF RUN SHOWS NOW
RETROGRADING UPPER RIDGE RETURNING EASTWARD AFTER WEEKEND.  THIS
WOULD SUGGEST CONTINUED WARMUP INTO NEXT WEEK.  WEAK SURFACE FRONT
MAY WANDER DOWN LK MICH ABOUT SUNDAY BUT PROSPECTS OF PRECIP WITH
BUILDING WARMTH ALOFT IS SPECULATIVE AT THIS POINT.  LOOKS LIKE
ENTIRE 7 DAY FORECAST WILL BE DRY.  KML

.CHI...FLASH FLOOD WRNG UNTIL ABOUT 4AM PORTIONS CHI METRO

In the hours before

Local storm report, Jul 8, 8:10 PM CST, 5 hours 50 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO, IL
910 PM CDT MON JUL 8 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0840 PM    0 POLO                    IL   WIND DAMAGE
07/08/02   OGLE                           LOTS OF TREES DOWN IN POLO
                                          AND BETWEEN POLO AND
                                          OREGONREPORTED BY LAW
                                          ENFORCEMENT

The radar

The Chicago radar (KLOT), 28 km away, was scanning. The volume nearest the first event began at 07:58 UTC.

Open the radar archive at this moment

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, Du Page

When: July 9, 2:00 AM CST to 3:30 AM CST
Where: Du Page County, Central Portion
Reported by: EMERGENCY MANAGER
Coordinates: 41.852, -88.086 (the zone’s center; the record gives no point)

Flash Flood, Kane

When: July 9, 2:00 AM CST to 3:30 AM CST
Where: Kane County, Central Portion
Reported by: EMERGENCY MANAGER
Coordinates: 41.939, -88.429 (the zone’s center; the record gives no point)

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

Every storm in Illinois in 2002 Every state in 2002 This day in weather history Warnings in Illinois, July 2002

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: 5303351, 5303352.