Thunderstorm Wind, De Kalb
- When
- August 15, 6:58 PM CST
- Where
- De Kalb County
- Coordinates
- 41.930, -88.870
Tornadoes and Damaging Winds in Illinois, August 15, 1978
3 thunderstorm wind, 3 tornado, as filed by the National Weather Service.
Where it happened
Every event with a place to put it. 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
- $750,000
- Crop damage
- None recorded
- Events
- 6
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.
Event by event
3 thunderstorm wind, 3 tornado. Local standard time, as filed.
Tornado, Mercer
- When
- August 15, 7:00 PM CST
- Where
- Mercer County
- Rating
- F3
- Path length
- 6.4 mi
- Path width
- 77 yd
- Property damage
- $250,000
- Coordinates
- 41.270, -90.780
Tornado, Rock Island
- When
- August 15, 7:13 PM CST
- Where
- Rock Island County
- Rating
- F3
- Path width
- 33 yd
- Property damage
- $250,000
- Coordinates
- 41.330, -90.680
Thunderstorm Wind, Rock Island
- When
- August 15, 7:15 PM CST
- Where
- Rock Island County
- Coordinates
- 41.400, -90.650
Tornado, McHenry
- When
- August 15, 7:45 PM CST
- Where
- McHenry County
- Rating
- F2
- Path length
- 2 mi
- Path width
- 100 yd
- Property damage
- $250,000
- Coordinates
- 42.180, -88.370
Thunderstorm Wind, Cook
- When
- August 15, 8:24 PM CST
- Where
- Cook County
- Measured
- 52 kt (60 mph)
- Coordinates
- 42.080, -87.820
What these are
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
- 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.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Tornadoes and Hail in Michigan, August 15, 1978
- Tornado and Hail in Wisconsin, August 15, 1978
- Hail and Damaging Winds in Oklahoma, August 15, 1978
- Tornadoes and Hail in Texas, August 15, 1978
- Damaging Wind in Kansas, August 15, 1978
- Damaging Wind in Minnesota, August 15, 1978
- Damaging Wind in Florida, August 15, 1978
- Damaging Wind in Missouri, August 15, 1978
- Tornado in Washington, August 15, 1978
More
Every storm in Illinois in 1978Every state in 1978This day in weather historyThe tornado archive for Illinois, 1978
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: 10004673, 10004674, 10004675, 10004676, 10004677, 10004678.