Alert archive / Iowa / Flash Flood Warnings in 2025

Flash Flood Warning 13, NWS La Crosse, WI

August 18, 20256 counties in Iowa

NWS La Crosse, WI issued this flash flood warning at Aug 18, 2025, 7:20 AM CDT for 6 counties in Iowa. It was in force for 4 hr. 8 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 18, 2025, 7:20 AM CDT (12:20 UTC)
Expired: Aug 18, 2025, 11:00 AM CDT
In force: 4 hr
Issued by: NWS La Crosse, WI
Area: Storm-based polygon
Flood severity: None

Counties Allamakee County, IA, Chickasaw County, IA, Floyd County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA

The radar

The La Crosse radar (KARX), 87 km from the middle of the area, began a volume at 12:22 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.

What was reported inside it

Time	Report	Where	Remark
Aug 18, 7:37 AM CDT	RAIN 4.5	2 Se Colwell, IA	Since 11 PM on 8/17.
Aug 18, 7:45 AM CDT	FLASH FLOOD	3 Sse Colwell, IA	Water over the road.
Aug 18, 7:55 AM CDT	FLASH FLOOD	2 Sse Decorah, IA	Minor water over Trout Run road.
Aug 18, 8:06 AM CDT	FLASH FLOOD	1 E Charles City, IA	Received from mPing. Minor flooding.
Aug 18, 8:13 AM CDT	FLASH FLOOD	1 E Devon, IA	Water flowing over the road at the intersection of 165th St and Kenwood Ave near Devon Woods.
Aug 18, 8:13 AM CDT	FLASH FLOOD	Devon, IA	Water over gravel road 165th street. Picture received on social media.
Aug 18, 8:17 AM CDT	RAIN 4.5	1 S Cresco, IA
Aug 18, 8:43 AM CDT	RAIN 4.07	Decorah, IA	Since midnight.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 0.3 hours before the alert went out and 215 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 116 J/kg
Mixed-layer CIN: -149 J/kg
Mixed-layer LCL: 598 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 125 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

123 
WGUS53 KARX 181220
FFWARX
IAC005-037-067-089-131-191-181600-
/O.NEW.KARX.FF.W.0013.250818T1220Z-250818T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
720 AM CDT Mon Aug 18 2025

The National Weather Service in La Crosse has issued a

* Flash Flood Warning for...
  Northeastern Floyd County in north central Iowa...
  Southeastern Mitchell County in north central Iowa...
  Northwestern Allamakee County in northeastern Iowa...
  Chickasaw County in northeastern Iowa...
  Southern Howard County in northeastern Iowa...
  Winneshiek County in northeastern Iowa...

* Until 1100 AM CDT.

* At 720 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 4 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Decorah, Charles City, Waukon, Cresco, New Hampton, Calmar, Elma, 
  Lawler, Spillville, Fort Atkinson, Floyd, Ridgeway, Ionia, 
  Protivin, Jerico, Chickasaw, Alta Vista, North Washington, Colwell 
  and Bassett.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4323 9275 4330 9255 4347 9208 4350 9198
      4350 9183 4350 9181 4350 9179 4350 9138
      4349 9140 4346 9134 4332 9130 4321 9162
      4308 9207 4308 9208 4308 9209 4291 9229
      4303 9277

FLASH FLOOD...RADAR INDICATED

$$

Baumgardt

1 follow-up statement

327 
WGUS73 KARX 181348
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
848 AM CDT Mon Aug 18 2025

IAC005-037-067-089-131-191-181600-
/O.CON.KARX.FF.W.0013.000000T0000Z-250818T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allamakee IA-Chickasaw IA-Floyd IA-Howard IA-Mitchell IA-
Winneshiek IA-
848 AM CDT Mon Aug 18 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 11 AM CDT THIS 
MORNING FOR NORTHEASTERN FLOYD, SOUTHEASTERN MITCHELL, NORTHWESTERN 
ALLAMAKEE, CHICKASAW, SOUTHERN HOWARD AND WINNESHIEK COUNTIES...

At 848 AM CDT, Reports of water over roads are increasing this 
morning. Rainfall reports of 3 to 5 inches have been received in the 
warning area and an additional inch of rain is expected. Flash 
flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and rainfall reports.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Decorah, Charles City, Waukon, Cresco, New Hampton, Calmar, Elma, 
  Lawler, Spillville, Fort Atkinson, Floyd, Ridgeway, Ionia, 
  Protivin, Jerico, Chickasaw, Alta Vista, North Washington, Colwell 
  and Bassett.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4323 9275 4330 9255 4347 9208 4350 9198
      4350 9183 4350 9181 4350 9179 4350 9138
      4349 9140 4346 9134 4332 9130 4321 9162
      4308 9207 4308 9208 4308 9209 4291 9229
      4303 9277

FLASH FLOOD...RADAR INDICATED

$$

Baumgardt

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 6:42 AM CDT	River Flood Warning	ARX	Allamakee	48 hr
Aug 18, 9:37 AM CDT	River Flood Warning	ARX	Floyd	59 hr
Aug 18, 11:02 AM CDT	Areal Flood Warning	ARX	Allamakee, Chickasaw, Floyd, Howard, Mitchell, Winneshiek	31 hr
Aug 18, 11:17 AM CDT	River Flood Warning	ARX	Winneshiek	43 hr
Aug 18, 1:04 PM CDT	River Flood Warning	ARX	Winneshiek	5 hr
Aug 18, 2:37 PM CDT	River Flood Watch	ARX	Clayton	62 hr

Nearby

Flash Flood Warnings in Iowa, 2025 Every flash flood warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.