Thunderstorm Wind, Hancock
- When
- August 15, 12:30 PM CST
- Where
- Hancock County
- Coordinates
- 43.230, -93.920
Tornadoes and Hail in Iowa, August 15, 1977
5 tornado, 4 thunderstorm wind, 4 hail, 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
- $525,000
- Crop damage
- None recorded
- Events
- 13
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
5 tornado, 4 thunderstorm wind, 4 hail. Local standard time, as filed.
Thunderstorm Wind, Hamilton
- When
- August 15, 3:00 PM CST
- Where
- Hamilton County
- Coordinates
- 42.470, -93.820
Hail, Story
- When
- August 15, 3:45 PM CST
- Where
- Story County
- Measured
- 1.75 in hail
- Coordinates
- 42.170, -93.400
Hail, Hamilton
- When
- August 15, 3:46 PM CST
- Where
- Hamilton County
- Measured
- 1.75 in hail
- Coordinates
- 42.250, -93.720
Thunderstorm Wind, Webster
- When
- August 15, 3:55 PM CST
- Where
- Webster County
- Measured
- 50 kt (58 mph)
- Coordinates
- 42.550, -94.180
Tornado, Monona
- When
- August 15, 4:00 PM CST
- Where
- Monona County
- Path length
- 0.2 mi
- Path width
- 20 yd
- Coordinates
- 41.970, -95.770
Thunderstorm Wind, Monona
- When
- August 15, 4:00 PM CST
- Where
- Monona County
- Coordinates
- 42.030, -96.100
Hail, Marshall
- When
- August 15, 5:20 PM CST
- Where
- Marshall County
- Measured
- 1.75 in hail
- Coordinates
- 42.050, -92.920
Tornado, Polk
- When
- August 15, 6:45 PM CST
- Where
- Polk County
- Path length
- 0.2 mi
- Path width
- 60 yd
- Coordinates
- 41.730, -93.600
Hail, Polk
- When
- August 15, 7:00 PM CST
- Where
- Polk County
- Measured
- 1.75 in hail
- Coordinates
- 41.730, -93.620
Tornado, Iowa
- When
- August 15, 8:30 PM CST
- Where
- Iowa County
- Path length
- 0.2 mi
- Path width
- 20 yd
- Property damage
- $25,000
- Coordinates
- 41.800, -92.070
Tornado, Johnson
- When
- August 15, 11:10 PM CST
- Where
- Johnson County
- Path length
- 2 mi
- Path width
- 60 yd
- Property damage
- $250,000
- Coordinates
- 41.580, -91.650
Tornado, Johnson
- When
- August 15, 11:15 PM CST
- Where
- Johnson County
- Path length
- 0.5 mi
- Path width
- 60 yd
- Property damage
- $250,000
- Coordinates
- 41.670, -91.600
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.
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
- 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
More
Every storm in Iowa in 1977Every state in 1977This day in weather historyThe tornado archive for Iowa, 1977
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: 10011569, 10011570, 10011571, 10011572, 10011573, 10011574, 10011575, 10011576, 10011577, 10011578, 10011579, 10011580, 10011581.