Flooding in Illinois, October 23, 2001

Name: Flooding in Illinois, October 23, 2001
Start: 2001-10-23T00:30
End: 2001-10-23T03:30
Location: Illinois

October 23, 2001 · NWS LOT · 2 events in 2 counties and zones

Heavy rain early in the morning on October 23rd caused minor street flooding in northern De Kalb county and many locations in Lake 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 early in the morning on October 23rd caused minor street flooding in northern De Kalb county and many locations in Lake county.

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 Oct 22, 1:41 PM CST, 10 hours 49 minutes earlier.

Area forecast discussion, Oct 22, 1:41 PM CST, 10 hours 49 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
230 CDT MON OCT 22 2001

THE WARM FRONT WILL MOVE NORTH OF THE FORECAST AREA OF NORTHEAST
ILLINOIS AND NORTHWEST INDIANA. THIS IS IN RESPONSE WITH A LOW IN
SOUTH DAKOTA. USING THE AVN MODEL THIS LOW IS EXPECTED TO TRACK EAST
FROM SOUTH DAKOTA AND INTO CENTRAL LAKE MICHIGAN. THE WATER VAPOR
LOOPS AND PROFILER DATA SHOWS THE JET STREAK MOVING INTO WESTERN
KANSAS AT 1815 UTC. THIS IS A LITTLE SLOWER THAN THIS MORNINGS RUN
OF THE AVN SO WILL ADJUST THE MOVEMENT OF SURFACE LOW A LITTLE
SLOWER. K INDEX AND LIFTED INDEX FORECASTS FOR SHOW ENOUGH
INSTABILITY FOR POSSIBLE THUNDERSTORMS FOR TONIGHT AND TUESDAY

FOR THIS EVENING THE SHOWERS AND THUNDERSTORMS FROM THE WARM FRONT
HAVE MOVED NORTH INTO WISCONSIN. OTHER SHOWERS AND THUNDERSTORMS IN
EASTERN IOWA ARE APPROACHING THE FORECAST AREA. DEWPOINTS WILL
INCREASE AS MOISTURE ADVECTION IS SEEN ON THE SURFACE MAP AND THE
MESO ETA SHOWS DEWPOINTS INCREASING BY 0000 UTC TUESDAY. WILL
MENTION HEAVY RAIN POSSIBLE IN THUNDERSTORMS BUT DECIDED TO HOLD OFF
ON A FLOOD WATCH.

ON TUESDAY THE LOW WILL MOVE NORTHEAST INTO WISCONSIN. THE FORECAST
AREA WILL BE IN WARM AIR THROUGHOUT THIS STORM SO CONVECTION IS IN
THE FORECAST ON TUESDAY. WILL PUT IN WINDY CONDITIONS AS THE
PRESSURE GRADIENT WILL BE RATHER LARGE. THE SECOND LOW WILL MOVE
INTO LAKE SUPERIOR DURING WEDNESDAY WITH A TRAILING COLD FRONT
MOVING ACROSS BY 0000 UTC THURSDAY. THIS IS A LITTLE SLOWER THAN THE
AVN MODEL. THIS FRONT WILL BRING IN THE COLD AIR. THE 500 MB
FORECAST FROM THE MRF SHOWS A LARGE WAVE MOVING OVER THE AREA
THURSDAY.

.CHI...NONE.

WHW

In the hours before

Special weather statement, Oct 22, 8:20 PM CST, 4 hours 10 minutes before

ILZ003>006-008-010>014-019>022-032-230250-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
920 PM CDT MON OCT 22 2001

SEVERE THUNDERSTORM WATCH NUMBER 794 FOR NORTH CENTRAL AND NORTHEAST
ILLINOIS IS CANCELLED.

ALTHOUGH SHOWERS AND SOME THUNDERSTORMS HAVE SPREAD OVER NORHTERN
ILLINOIS...THE INTENSITY OF THE STORMS HAS DECREASED SINCE EARLY
THIS EVENING. IT APPEARS THAT THE STORMS WILL NO LONGER POSE A
THREAT.

SOMREK

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 flood. Local standard time, as filed.

Flood, De Kalb

When: October 23, 12:30 AM CST to 3:00 AM CST
Where: De Kalb County, De Kalb
Reported by: LAW ENFORCEMENT
Coordinates: 41.894, -88.770 (the zone’s center; the record gives no point)

Flood, Lake

When: October 23, 12:30 AM CST to 3:30 AM CST
Where: Lake County, Countywide
Reported by: LAW ENFORCEMENT
Coordinates: 42.349, -87.862 (the zone’s center; the record gives no point)

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Illinois in 2001 Every state in 2001 This day in weather history Warnings in Illinois, October 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: 5270857, 5270858.