Illinois, 1999

Tornado and Flash Flood in Illinois, May 12, 1999

May 12, 1999 · NWS LOT · 3 events in 1 county or zone

A series of strong slow moving thunderstorms hit western Ogle County. Funnel clouds or weak landspout tornadoes were reported southeast of Brookville and northwest of Polo.

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

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

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.

A series of strong slow moving thunderstorms hit western Ogle County. Funnel clouds or weak landspout tornadoes were reported southeast of Brookville and northwest of Polo. As many a 4 were spotted. There was no damage. Golf ball size hail was reported south of Forreston. The storms dumped heavy rain over parts of western Ogle County from mid afternoon well into the evening hours. Doppler radar indicated as much as 6 and a half inches of rain fell in a couple hours. The heavy rain caused flooding of low areas and creeks. Highway 64 was closed due to high water. The most serious flooding was along Pine Creek. The flooded creek washed out 3 sections of Lowell Park Road and two bridges. A car was stranded by rising flood waters on a bridge on Lowell Park Road. The driver had to be rescued by a tractor. Flooding of Pine Creek caused damage to White Pines State Park. A bridge was washed out. Flood waters swept about 30 picnic tables away. Two homes across the road from the park were flooded. The deck of one house was washed away.

The radar

The Quad Cities radar (KDVN), 91 km away, was scanning. The volume nearest the first event began at 20:42 UTC.

Open the radar archive at this moment

Event by event

1 tornado, 1 hail, 1 flash flood. Local standard time, as filed.

Tornado, Ogle

When
May 12, 2:45 PM CST to 3:10 PM CST
Where
Ogle County, Brookville to 2 mi NW of Polo
Rating
F0
Path length
1 mi
Path width
20 yd
Reported by
EMERGENCY MANAGER
Coordinates
42.050, -89.650

Hail, Ogle

When
May 12, 3:55 PM CST
Where
Ogle County, 4 mi S of Forreston
Measured
1.75 in hail
Reported by
EMERGENCY MANAGER
Coordinates
42.070, -89.580

Flash Flood, Ogle

When
May 12, 4:45 PM CST to 11:00 PM CST
Where
Ogle County, West Portion
Reported by
EMERGENCY MANAGER
Coordinates
42.043, -89.321 (the zone’s center; the record gives no point)

What these are

Tornado
A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Hail
Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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

More

Every storm in Illinois in 1999Every state in 1999This day in weather historyThe tornado archive for Illinois, 1999Warnings in Illinois, May 1999

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: 5696622, 5696623, 5696624.