Alert archive / Iowa / Flash Flood Warnings in 2017

Flash Flood Warning 20, NWS La Crosse, WI

July 21, 2017Chickasaw County, Floyd County, Iowa

NWS La Crosse, WI issued this flash flood warning at Jul 21, 2017, 11:54 PM CDT for Chickasaw County, Floyd County, Iowa. It was in force for 10 hr. 12 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
Jul 21, 2017, 11:54 PM CDT (04:54 UTC)
Expired
Jul 22, 2017, 9:46 AM CDT
In force
10 hr
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Flood severity
None

Counties Chickasaw County, IA, Floyd County, IA

The radar

The La Crosse radar (KARX), 141 km from the middle of the area, began a volume at 04:56 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

TimeReportWhereRemark
Jul 22, 2:25 AM CDTHEAVY RAIN 3.843 E Charles City, IATHE DURATION OF THE HEAVY RAIN EVENT WAS 4 HOURS.
Jul 22, 2:25 AM CDTHEAVY RAIN 3.843 E Charles City, IA
Jul 22, 3:00 AM CDTFLASH FLOOD5 Nw Nashua, IAPARTIAL WASHOUT OF A ROAD NEAR THE INTERSECTION OF 240TH STREET AND VISTA LANE.
Jul 22, 3:00 AM CDTFLASH FLOOD5 Sw Bassett, IAPARTIAL WASHOUT OF RAILROAD CROSSING NEAR THE INTERSECTION OF WALNUT AVENUE AND 230TH STREET.
Jul 22, 6:45 AM CDTHEAVY RAIN 2.43 Sse Rockford, IAMESONET STATION RKFI4, ROCKFORD-SHELL ROCK RVR.
Jul 22, 6:55 AM CDTHEAVY RAIN 5.013 E Charles City, IAAWOS STATION CCY, CHARLES CITY AIRPORT.
Jul 22, 7:00 AM CDTHEAVY RAIN 5.58New Hampton, IACOCORAHS STATION IA-CW-3, NEW HAMPTON.
Jul 22, 7:00 AM CDTHEAVY RAIN 5.99New Hampton, IACOCORAHS STATION IA-CW-2, NEW HAMPTON.
Jul 22, 7:00 AM CDTHEAVY RAIN 6.631 Sse Charles City, IACO-OP OBSERVER STATION CIYI4, CHARLES CITY.
Jul 22, 7:00 AM CDTHEAVY RAIN 7New Hampton, IASTORM TOTAL.
Jul 22, 7:30 AM CDTHEAVY RAIN 6.011 Sse Charles City, IAMESONET STATION CCYI4, CHARLES CITY-CEDAR RIVER.
Jul 22, 7:30 AM CDTHEAVY RAIN 6.01Charles City, IAMESONET STATION CCYI4, CHARLES CITY-CEDAR RIVER.

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 00:00Z, 4.9 hours before the alert went out and 212 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-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2017-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 337 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2017-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
337 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
981 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
40 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

620 
WGUS53 KARX 220454
FFWARX
IAC037-067-221045-
/O.NEW.KARX.FF.W.0020.170722T0454Z-170722T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
1154 PM CDT FRI JUL 21 2017

The National Weather Service in La Crosse has issued a

* Flash Flood Warning for...
  Floyd County in north central Iowa...
  Northern Chickasaw County in northeastern Iowa...

* Until 545 AM CDT

* At 1152 PM CDT, law enforcement reports thunderstorms producing 
  heavy rain and flash flooding across the warned area. 2 to 3 
  inches of have fallen since 10 pm, with another 1 to 3 inches 
  expected through early morning. Flash flooding has been reported 
  in Charles City, and is likely ongoing in many other areas.

* Some locations that will experience flooding include...
  Charles City, New Hampton, Nashua, Nora Springs, Rockford, Lawler,
  Rudd, Floyd, Marble Rock, North Washington, Colwell, County Roads V
  56 And B 33, County Roads B 60 And T 64, County Roads B 33 And T
  76, County Roads B 20 And T 26, Carrville, Highway 14 And County
  Road B 60, Little Turkey, Roseville and Oakwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4320 9302 4316 9208 4304 9208 4307 9255
      4295 9255 4297 9302

$$

Lawrence
4 follow-up statements
029 
WGUS73 KARX 220714
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
214 AM CDT SAT JUL 22 2017

IAC037-067-221045-
/O.CON.KARX.FF.W.0020.000000T0000Z-170722T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Floyd IA-Chickasaw IA-
214 AM CDT SAT JUL 22 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 AM CDT FOR
FLOYD AND NORTHERN CHICKASAW COUNTIES...

At 208 AM CDT, local law enforcement reported continued flash 
flooding across the area, with several reports of water flowing over 
roads.

Rainfall is gradually coming to an end across the area, though flash 
flooding will continue through sunrise as runoff continues.

Some locations that will experience flooding include...
Charles City, New Hampton, Nashua, Nora Springs, Rockford, Lawler,
Rudd, Floyd, Marble Rock, North Washington, Colwell, County Roads V
56 And B 33, County Roads B 60 And T 64, County Roads B 33 And T 76,
County Roads B 20 And T 26, Carrville, Highway 14 And County Road B
60, Little Turkey, Roseville and Oakwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4320 9302 4316 9208 4304 9208 4307 9255
      4295 9255 4297 9302

$$

DL
415 
WGUS73 KARX 220755
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
255 AM CDT SAT JUL 22 2017

IAC037-067-221045-
/O.CON.KARX.FF.W.0020.000000T0000Z-170722T1045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Floyd IA-Chickasaw IA-
255 AM CDT SAT JUL 22 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 AM CDT FOR
FLOYD AND NORTHERN CHICKASAW COUNTIES...

At 253 AM CDT, local law enforcement reported flash flooding across 
parts of the area. The heaviest rain has shifted south of the area 
but flash flooding continues, especially over Chickasaw county. Some 
roads may be washed out in spots or have water flowing over them. 

Some locations that will experience flooding include...
Charles City, New Hampton, Nashua, Nora Springs, Rockford, Lawler,
Rudd, Floyd, Marble Rock, North Washington, Colwell, County Roads V
56 And B 33, County Roads B 60 And T 64, County Roads B 33 And T 76,
County Roads B 20 And T 26, Carrville, Highway 14 And County Road B
60, Little Turkey, Roseville and Oakwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4320 9302 4316 9208 4304 9208 4307 9255
      4295 9255 4297 9302

$$

Wetenkamp
389 
WGUS53 KARX 221015
FFWARX
IAC037-067-221515-
/O.EXT.KARX.FF.W.0020.000000T0000Z-170722T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service La Crosse WI
515 AM CDT SAT JUL 22 2017

The National Weather Service in La Crosse has extended the

* Flash Flood Warning for...
  Floyd County in north central Iowa...
  Northern Chickasaw County in northeastern Iowa...

* Until 1015 AM CDT

* At 513 AM CDT, some areas of flash flooding continue, especially 
  across southern portions of Floyd County due to 3 to 7 inches of 
  earlier rainfall.

* Some locations that will experience flooding may include...
  Charles City, New Hampton, Nashua, Nora Springs, Rockford, Lawler,
  Rudd, Floyd, Marble Rock, North Washington, Colwell, County Roads V
  56 And B 33, County Roads B 60 And T 64, County Roads B 33 And T
  76, County Roads B 20 And T 26, Carrville, Highway 14 And County
  Road B 60, Little Turkey, Roseville and Oakwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4320 9302 4316 9208 4304 9208 4307 9255
      4295 9255 4297 9302

$$

Lawrence
008 
WGUS73 KARX 221446
FFSARX

Flash Flood Statement
National Weather Service La Crosse WI
946 AM CDT SAT JUL 22 2017

IAC037-067-221453-
/O.CAN.KARX.FF.W.0020.000000T0000Z-170722T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Floyd IA-Chickasaw IA-
946 AM CDT SAT JUL 22 2017

...THE FLASH FLOOD WARNING FOR FLOYD AND NORTHERN CHICKASAW COUNTIES
IS CANCELLED...

Law enforcement reported that flood waters have receded but numerous 
roads are washed out. Flooding is no longer expected to pose a 
threat but please continue to heed any road closures.

LAT...LON 4320 9302 4316 9208 4304 9208 4307 9255
      4295 9255 4297 9302

$$

DAS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 21, 9:06 PM CDTRiver Flood WarningARXClayton38 hr
Jul 21, 9:06 PM CDTRiver Flood WarningARXClayton63 hr
Jul 21, 10:18 PM CDTFlash Flood WarningARXChickasaw, Clayton, Fayette12 hr
Jul 22, 1:21 AM CDTSevere Thunderstorm WarningARXChickasaw, Howard, Winneshiek39 min
Jul 22, 9:56 AM CDTAreal Flood WarningARXClayton24 hr
Jul 22, 10:09 AM CDTAreal Flood WarningARXChickasaw, Clayton, Fayette24 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.