Thunderstorm Wind, Polk
- When
- July 20, 3:07 PM CST
- Where
- Polk County, Ankeny Arpt
- Measured
- 54 kt (62 mph)
- Property damage
- $3,000
- Coordinates
- 41.700, -93.580
Damaging Wind in Iowa, July 20, 1997
The synoptic situation was similar to the day prior with a stationary frontal boundary located to the north of Iowa. An upper level low pressure moved out of Kansas into southwest Iowa during the afternoon and evening hours.
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
- $3,000
- 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 DMX wrote it up.
The synoptic situation was similar to the day prior with a stationary frontal boundary located to the north of Iowa. An upper level low pressure moved out of Kansas into southwest Iowa during the afternoon and evening hours. The airmass was very unstable with CAPE values of 4000 J/kg with surface dew point temperatures in the low to mid 70s. Most of the storms were not severe, however a few did become "pulse severe". One cell dropped one inch diameter hail in West Des Moines. In what was an apparent downburst, 70 MPH winds downed large trees and caused damage in a small section of West Des Moines. There was no damage further northeast from the storm. Later another cell produced another apparent downburst over the Ankeny airport with 62 MPH winds. Little damage was reported from that event however.
The radar
The Des Moines radar (KDMX), 12 km away, was scanning. The volume nearest the first event began at 21:05 UTC.
Event by event
1 thunderstorm wind. Local standard time, as filed.
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.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Heat in Missouri, July 20, 1997
- Lightning Strikes and Heavy Rain in Wisconsin, July 20 to 21, 1997
- Damaging Wind in Iowa, July 20, 1997
- Tornado in Iowa, July 20, 1997
- Damaging Wind in Iowa, July 20, 1997
- Damaging Wind in Iowa, July 20, 1997
- Damaging Wind in Iowa, July 20, 1997
- Flash Flood and Hail in Oklahoma, July 20, 1997
- Lightning Strike in Florida, July 20, 1997
- Tornado in Minnesota, July 20 to 21, 1997
- Tornadoes and Hail in Minnesota, July 20, 1997
- Funnel Clouds in Wisconsin, July 20, 1997
More
Every storm in Iowa in 1997Every state in 1997This day in weather historyWarnings in Iowa, July 1997
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: 5603027.