Alert archive / Iowa / Flash Flood Warnings in 2021
Flash Flood Warning 5, NWS Des Moines, IA
NWS Des Moines, IA issued this flash flood warning at Aug 27, 2021, 8:21 PM CDT for 4 counties in Iowa. It was in force for 6 hr. 5 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 27, 2021, 8:21 PM CDT (01:21 UTC)
- Expired
- Aug 28, 2021, 2:00 AM CDT
- In force
- 6 hr
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Flood severity
- None
Counties Cerro Gordo County, IA, Hancock County, IA, Winnebago County, IA, Worth County, IA
The radar
The Minneapolis radar (KMPX), 172 km from the middle of the area, began a volume at 01:23 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 27, 8:57 PM CDT | HEAVY RAIN 5.83 | Grafton, IA | DAILY TOTAL SINCE MIDNIGHT. |
| Aug 27, 9:48 PM CDT | FLASH FLOOD | Northwood, IA | WATER SEVERAL INCHES DEEP COMPLETELY COVERING 13TH STREET SOUTH IN NORTHWOOD. |
| Aug 27, 10:12 PM CDT | FLASH FLOOD | 2 Ne Grafton, IA | WATER, SEVERAL INCHES DEEP FLOWING OVER YARROW AVE NEAR THE INTERSECTION OF 410TH STREET. |
| Aug 27, 10:22 PM CDT | FLASH FLOOD | Grafton, IA | WATER 2-3 FEET DEEP FLOWING UP TO ROAD ON SOUTH END OF TOWN AS WELL AS APPROACHING A RESIDENT. 3-6 INCHES OF WATER FLOWING OVER ROAD. REPORT VIA SOCIAL MEDIA AND COURTESY OF KAALTV. |
| Aug 27, 10:34 PM CDT | FLASH FLOOD | 2 Nw Grafton, IA | WATER SEVERAL INCHES DEEP FLOWING OVER ROAD NEAR THE INTERSECTION OF ULMUS AVE AND 410TH STREET EAST OF KENSETT. |
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, 1.4 hours before the alert went out and 172 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
- 652 J/kg
- Mixed-layer CIN
- -66 J/kg
- Mixed-layer LCL
- 643 m above ground
- 0-6 km bulk shear
- 45 kt
- 0-1 km storm-relative helicity
- 140 m²/s²
- 0-3 km storm-relative helicity
- 175 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.5
The text
As transmitted.
317
WGUS53 KDMX 280121
FFWDMX
IAC033-081-189-195-280700-
/O.NEW.KDMX.FF.W.0005.210828T0121Z-210828T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Des Moines IA
821 PM CDT Fri Aug 27 2021
The National Weather Service in Des Moines has issued a
* Flash Flood Warning for...
Northern Cerro Gordo County in north central Iowa...
Northeastern Hancock County in north central Iowa...
Eastern Winnebago County in north central Iowa...
Worth County in north central Iowa...
* Until 200 AM CDT.
* At 821 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across 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...
Mason City, Forest City, Northwood, Lake Mills, Manly, Rice Lake,
Plymouth, Fertile, Leland, Kensett, Grafton, Hanlontown, Joice,
Rock Falls, Scarville, Bolan, Northwood Municipal, Rice Lake State
Park, Lake Mills Municipal Airport and Pilot Knob State Park.
Portions of northern Worth County have received over 6 inches of
rainfall so far today via radar estimated.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4325 9367 4350 9366 4350 9302 4316 9302
4319 9349
FLASH FLOOD...RADAR INDICATED
$$
Podrazik3 follow-up statements
404
WGUS73 KDMX 280252
FFSDMX
Flash Flood Statement
National Weather Service Des Moines IA
952 PM CDT Fri Aug 27 2021
IAC033-081-189-195-280700-
/O.CON.KDMX.FF.W.0005.000000T0000Z-210828T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cerro Gordo IA-Hancock IA-Winnebago IA-Worth IA-
952 PM CDT Fri Aug 27 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 2 AM CDT SATURDAY FOR
NORTHERN CERRO GORDO, NORTHEASTERN HANCOCK, EASTERN WINNEBAGO AND
WORTH COUNTIES...
At 952 PM CDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 3 and 6 inches of rain have
fallen. The expected rainfall rate is 2 to 3 inches in 1 hour.
Additional rainfall amounts of 1 to 2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Mason City, Forest City, Northwood, Lake Mills, Manly, Rice Lake,
Plymouth, Fertile, Leland, Kensett, Grafton, Hanlontown, Joice,
Rock Falls, Scarville, Bolan, Northwood Municipal, Rice Lake State
Park, Lake Mills Municipal Airport and Pilot Knob State Park.
This includes the following highways...
Interstate 35 between mile markers 198 and 218.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4325 9367 4350 9366 4350 9302 4316 9302
4319 9349
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...2-3 INCHES IN 1 HOUR
$$
Podrazik313
WGUS73 KDMX 280423
FFSDMX
Flash Flood Statement
National Weather Service Des Moines IA
1123 PM CDT Fri Aug 27 2021
IAC081-189-280433-
/O.CAN.KDMX.FF.W.0005.000000T0000Z-210828T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hancock IA-Winnebago IA-
1123 PM CDT Fri Aug 27 2021
...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN HANCOCK AND
EASTERN WINNEBAGO COUNTIES...
Flooding is no longer expected to pose a threat. Please continue to
heed remaining road closures.
LAT...LON 4350 9350 4350 9302 4316 9302 4319 9350
$$
IAC033-195-280700-
/O.CON.KDMX.FF.W.0005.000000T0000Z-210828T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cerro Gordo IA-Worth IA-
1123 PM CDT Fri Aug 27 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 2 AM CDT SATURDAY FOR
NORTHERN CERRO GORDO AND WORTH COUNTIES...
At 1123 PM CDT, local law enforcement reported water of several
inches deep covering the road near the intersection of 430th and
Yarrow Ave and 410th and Ulmus. Both intersections are east of
Kensett and north of Grafton. So far tonight, between 3 and 7 inches
of rain have fallen. Flash flooding is expected to continue.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Law enforcement reported.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Mason City, Northwood, Manly, Rice Lake, Plymouth, Fertile,
Kensett, Grafton, Hanlontown, Joice, Rock Falls, Bolan, Northwood
Municipal and Rice Lake State Park.
This includes the following highways...
Interstate 35 between mile markers 198 and 218.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4350 9350 4350 9302 4316 9302 4319 9350
FLASH FLOOD...OBSERVED
$$
Podrazik387 WGUS73 KDMX 280706 FFSDMX Flash Flood Statement National Weather Service Des Moines IA 206 AM CDT Sat Aug 28 2021 IAC033-195-280716- /O.EXP.KDMX.FF.W.0005.000000T0000Z-210828T0700Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Cerro Gordo IA-Worth IA- 206 AM CDT Sat Aug 28 2021 ...FLASH FLOOD WARNING HAS EXPIRED FOR NORTHERN CERRO GORDO AND WORTH COUNTIES... The heavy rain has ended. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures. LAT...LON 4350 9350 4350 9302 4316 9302 4319 9350 $$ Martin
The office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 27, 7:10 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Worth | 65 min |
| Aug 27, 8:15 PM CDT | Severe Thunderstorm Warning | DMX | Cerro Gordo, Worth | 30 min |
| Aug 28, 10:17 AM CDT | River Flood Warning | DMX | Black Hawk, Bremer, Butler | 3 days |
| Aug 28, 10:17 AM CDT | River Flood Warning | DMX | Black Hawk | 4 days |
Nearby
Flash Flood Warnings in Iowa, 2021Every flash flood warning in 2021
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.