Alert archive / Iowa / Flash Flood Warnings in 2017
Flash Flood Warning 2, NWS Sioux Falls, SD
NWS Sioux Falls, SD issued this flash flood warning at Aug 21, 2017, 12:48 AM CDT for Ida County, Woodbury County, Iowa. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2017, 12:48 AM CDT (05:48 UTC)
- Expired
- Aug 21, 2017, 3:45 AM CDT
- In force
- 3 hr
- Issued by
- NWS Sioux Falls, SD
- Area
- Storm-based polygon
- Flood severity
- None
Counties Ida County, IA, Woodbury County, IA
The radar
The Omaha radar (KOAX), 116 km from the middle of the area, began a volume at 05:50 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Omaha, NE (KOAX), launched 00:00Z, 5.8 hours before the alert went out and 116 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1704 J/kg
- Mixed-layer CIN
- -211 J/kg
- Mixed-layer LCL
- 1354 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 144 m²/s²
- 0-3 km storm-relative helicity
- 264 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
366 WGUS53 KFSD 210548 FFWFSD IAC093-193-210845- /O.NEW.KFSD.FF.W.0002.170821T0548Z-170821T0845Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ BULLETIN - EAS ACTIVATION REQUESTED Flash Flood Warning National Weather Service Sioux Falls SD 1248 AM CDT MON AUG 21 2017 The National Weather Service in Sioux Falls has issued a * Flash Flood Warning for... Southeastern Woodbury County in west central Iowa... Southwestern Ida County in west central Iowa... * Until 345 AM CDT * At 1247 AM CDT, Doppler radar indicated thunderstorms producing heavy rain across the warned area. Radar estimates show 2 to 4 inches of rain have fallen, and additional amounts of 1 to 2 inches are possible through 2 am. Flash flooding is expected to begin shortly. * Some locations that will experience flooding include... Danbury, Smithland and Oto. PRECAUTIONARY/PREPAREDNESS ACTIONS... Be especially cautious at night when it is harder to recognize the dangers of flooding. && LAT...LON 4221 9598 4236 9594 4233 9568 4221 9533 $$ JH
2 follow-up statements
667 WGUS73 KFSD 210725 FFSFSD Flash Flood Statement National Weather Service Sioux Falls SD 225 AM CDT MON AUG 21 2017 IAC093-193-210845- /O.CON.KFSD.FF.W.0002.000000T0000Z-170821T0845Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Woodbury IA-Ida IA- 225 AM CDT MON AUG 21 2017 ...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM CDT FOR SOUTHEASTERN WOODBURY AND SOUTHWESTERN IDA COUNTIES... At 221 AM CDT, Doppler radar indicates thunderstorms have diminished across the area. However, radar estimates show 3 to 5 inches of rain have fallen across the area since 1130 pm Sunday evening, with the heaviest amounts likely between Oto and Danbury in southeast Woodbury County. Some locations that will experience flooding include... Danbury, Smithland and Oto. PRECAUTIONARY/PREPAREDNESS ACTIONS... Be especially cautious at night when it is harder to recognize the dangers of flooding. && LAT...LON 4221 9598 4236 9594 4233 9568 4221 9533 $$ JH
787 WGUS73 KFSD 210838 FFSFSD Flash Flood Statement National Weather Service Sioux Falls SD 338 AM CDT MON AUG 21 2017 IAC093-193-210846- /O.EXP.KFSD.FF.W.0002.000000T0000Z-170821T0845Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Woodbury IA-Ida IA- 338 AM CDT MON AUG 21 2017 ...THE FLASH FLOOD WARNING FOR SOUTHEASTERN WOODBURY AND SOUTHWESTERN IDA COUNTIES WILL EXPIRE AT 345 AM CDT... The heavy rain has ended in the warned area, and flooding is no longer expected to pose a threat. Please continue to use caution while driving through the early morning, and avoid any flooded roadways. LAT...LON 4221 9598 4236 9594 4233 9568 4221 9533 $$ JH
The office that day
Everything else NWS Sioux Falls, SD issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 11:12 PM CDT | Severe Thunderstorm Warning | FSD | Ida | 23 min |
| Aug 21, 1:54 AM CDT | Severe Thunderstorm Warning | FSD | Clay | 24 min |
| Aug 21, 2:11 PM CDT | Severe Thunderstorm Warning | FSD | Lyon, Plymouth, Sioux | 49 min |
Nearby
Flash Flood Warnings in Iowa, 2017Every flash flood warning in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.