Tornado, Johnson
- When
- August 11, 6:21 PM MST to 6:23 PM MST
- Where
- Johnson County, 25 mi ENE of Kaycee
- Rating
- F1
- Path length
- 0.2 mi
- Path width
- 75 yd
- Property damage
- $8,000
- Reported by
- GENERAL PUBLIC
- Coordinates
- 43.850, -106.180
Tornado in Wyoming, August 11, 1999
Tornado touched down at Cogema-Irigaray uranium mine. Path length, width, and intensity are estimates.
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
- $8,000
- Crop damage
- None recorded
- Events
- 1
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 RIW wrote it up.
Tornado touched down at Cogema-Irigaray uranium mine. Path length, width, and intensity are estimates.
The radar
The Riverton/Lander radar (KRIW), 205 km away, was scanning. The volume nearest the first event began at 01:21 UTC.
Event by event
1 tornado. Local standard time, as filed.
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.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Tornado in Utah, August 11, 1999
- Hail and Damaging Wind in Kansas, August 11 to 26, 1999
- Hail and Damaging Wind in South Dakota, August 11, 1999
- Hail in Colorado, August 11, 1999
- Damaging Winds in Missouri, August 11, 1999
- Hail and Damaging Winds in Virginia, August 11, 1999
- Tornado in North Dakota, August 11, 1999
- Hail in Colorado, August 11, 1999
- Hail and Damaging Winds in Wyoming, August 11, 1999
- Hail and Lightning Strike in South Dakota, August 11, 1999
- Hail and Damaging Winds in North Carolina, August 11, 1999
- Hail and Damaging Winds in South Dakota, August 11 to 12, 1999
More
Every storm in Wyoming in 1999Every state in 1999This day in weather historyThe tornado archive for Wyoming, 1999Warnings in Wyoming, August 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: 5710245.