Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 172, NWS Sioux Falls, SD

December 15, 20215 counties in Iowa

NWS Sioux Falls, SD issued this severe thunderstorm warning at Dec 15, 2021, 4:05 PM CST for 5 counties in Iowa. It was in force for 55 min. 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
Dec 15, 2021, 4:05 PM CST (22:05 UTC)
Expired
Dec 15, 2021, 5:00 PM CST
In force
55 min
Issued by
NWS Sioux Falls, SD
Area
Storm-based polygon
Tornado
Possible
Damage threat
Considerable
Hail
0.75 in
Wind
70.0 mph

Counties Buena Vista County, IA, Cherokee County, IA, Ida County, IA, Plymouth County, IA, Woodbury County, IA

The radar

The Sioux Falls radar (KFSD), 120 km from the middle of the area, began a volume at 22:07 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
Dec 15, 4:34 PM CSTTSTM WND DMG1 W Anthon, IACATTLE BARN AND GARAGE DAMAGED. TIME ESTIMATED FROM RADAR.
Dec 15, 4:35 PM CSTTSTM WND DMGKingsley, IAROOF TOWN OFF OF BUILDING. TIME ESTIMATED FROM RADAR.
Dec 15, 4:43 PM CSTTSTM WND DMG2 Nw Battle Creek, IAMACHINE SHED DAMAGED. TIME ESTIMATED FROM RADAR.
Dec 15, 4:48 PM CSTTSTM WND DMG6 Nw Ida Grove, IAMACHINE SHED DAMAGE. TIME ESTIMATED FROM RADAR.
Dec 15, 4:50 PM CSTTSTM WND DMG4 Sse Holstein, IATREES DOWN. TIME ESTIMATED FROM RADAR.
Dec 15, 4:52 PM CSTTSTM WND DMG6 Ssw Cleghorn, IAMACHINE SHED DESTROYED AND GRAVITY WAGON TIPPED OVER. REPORT VIA SOCIAL MEDIA.
Dec 15, 4:56 PM CSTTSTM WND DMG1 Ssw Marcus, IAROOFS WERE BLOWN OFF OF A FEW BUILDINGS AND SEMI WAS BLOWN OFF THE ROAD. TIME ESTIMATED FROM RADAR.
Dec 15, 4:57 PM CSTTSTM WND DMG2 Nnw Galva, IAHOUSE DAMAGED WITH ROOF TORN OFF. HOOP BARN DESTROYED AND 100 YEAR OLD MARCHINE SHED DESTOYED. TIME ESTIMATED FROM RADAR.
Dec 15, 5:01 PM CSTTSTM WND DMG5 Sw Alta, IANUMEROUS TREES AND BRANCHES DOWN. REPORT RECEIVED VIA SOCIAL MEDIA. TIME ESTIMATED FROM RADAR.
Dec 15, 5:03 PM CSTTSTM WND DMGAurelia, IASILO DAMAGED, TREES DOWN AND SHEET METAL FROM BUILDINGS ON ROAD. POWER OUT IN TOWN. TIME ESTIMATED FROM RADAR.
Dec 15, 5:03 PM CSTTSTM WND DMGAurelia, IAUPDATES PREVIOUS TSTM WND DMG REPORT FROM AURELIA. SILO DAMAGED, TREES DOWN AND SHEET METAL FROM BUILDINGS ON ROAD. 3 RAIL CARS BLOWN OVER, AND A HOME DESTROYED. POWER OUT IN TOWN. TIME ESTIMATED FROM RADAR.
Dec 15, 5:04 PM CSTTSTM WND DMGLarrabee, IADAMAGE TO MACHINE SHEDS AND SOME ROOFS DAMAGE. TIME ESTIMATED FROM RADAR.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Dec 15, 1:23 PM CSTTornado WatchSPC7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.1 hours before the alert went out and 152 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, Omaha, NE at 12:00Z on 2021-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 12:00Z on 2021-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 346 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2165 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
346 m²/s²
0-3 km storm-relative helicity
384 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

215 
WUUS53 KFSD 152205
SVRFSD
IAC021-035-093-149-193-152300-
/O.NEW.KFSD.SV.W.0172.211215T2205Z-211215T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Sioux Falls SD
405 PM CST Wed Dec 15 2021

The National Weather Service in Sioux Falls has issued a

* Severe Thunderstorm Warning for...
  Cherokee County in northwestern Iowa...
  Eastern Woodbury County in west central Iowa...
  Plymouth County in northwestern Iowa...
  Southwestern Buena Vista County in northwestern Iowa...
  Ida County in west central Iowa...

* Until 500 PM CST.

* At 403 PM CST, severe thunderstorms were located along a line
  extending from Allen to near Winnebago to 8 miles northeast of
  Craig, moving northeast at 65 mph.

  HAZARD...70 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Severe thunderstorms will be near...
  Kingsley, Smithland, Merrill and Pierson around 430 PM CST.
  Danbury, Washta and Craig around 440 PM CST.
  Le Mars, Battle Creek, Quimby and Struble around 445 PM CST.
  Ida Grove, Cleghorn and Cushing around 450 PM CST.
  Cherokee and Holstein around 455 PM CST.
  
Other locations impacted by these severe thunderstorms include Oyens,
Oto, Brunsville, Meriden, Westfield and Chatsworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for northwestern
and west central Iowa...and southeastern South Dakota.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across parts of Nebraska. SEEK SHELTER NOW inside a 
sturdy structure and stay away from windows! A Tornado Watch remains 
in effect until 800 PM CST for northwestern and west central 
Iowa...and southeastern South Dakota.

&&

LAT...LON 4270 9607 4273 9663 4277 9663 4283 9658
      4284 9655 4289 9654 4291 9652 4291 9538
      4256 9533 4256 9539 4248 9539 4247 9532
      4222 9533 4221 9603
TIME...MOT...LOC 2203Z 225DEG 58KT 4243 9686 4225 9636 4189 9628 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

Weisser
1 follow-up statement
281 
WWUS53 KFSD 152236
SVSFSD

Severe Weather Statement
National Weather Service Sioux Falls SD
436 PM CST Wed Dec 15 2021

IAC021-035-093-149-193-152300-
/O.CON.KFSD.SV.W.0172.000000T0000Z-211215T2300Z/
Cherokee IA-Woodbury IA-Plymouth IA-Buena Vista IA-Ida IA-
436 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 500 PM CST
FOR CHEROKEE...EASTERN WOODBURY...PLYMOUTH...SOUTHWESTERN BUENA VISTA
AND IDA COUNTIES...

At 435 PM CST, severe thunderstorms were located along a line
extending from 8 miles northwest of Merrill to near Pierson to near
Danbury, moving northeast at 65 mph.

HAZARD...80 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be heavily damaged. Expect 
         considerable damage to roofs, windows, and vehicles. 
         Extensive tree damage and power outages are likely.

These severe storms will be near...
  Washta around 440 PM CST.
  Le Mars, Battle Creek, Quimby and Struble around 445 PM CST.
  Ida Grove, Cleghorn and Cushing around 450 PM CST.
  Cherokee and Holstein around 455 PM CST.
  Galva and Larrabee around 500 PM CST.

Other locations impacted by these severe thunderstorms include Oyens,
Oto, Brunsville, Meriden, Westfield and Chatsworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for northwestern
and west central Iowa...and southeastern South Dakota.

This is a DANGEROUS SITUATION. These storms are producing widespread 
wind damage across parts of Nebraska as well as tornadoes in parts 
of Woodbury county. SEEK SHELTER NOW inside a sturdy structure and 
stay away from windows.
 
&&

LAT...LON 4270 9607 4273 9663 4277 9663 4283 9658
      4284 9655 4289 9654 4291 9652 4291 9538
      4256 9533 4256 9539 4248 9539 4247 9532
      4222 9533 4221 9603
TIME...MOT...LOC 2235Z 225DEG 58KT 4278 9639 4260 9589 4224 9581 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Weisser

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 2:56 AM CSTDense Fog AdvisoryFSDBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 5 more6 hr
Dec 15, 3:23 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDPlymouth, Woodbury67 min
Dec 15, 4:00 PM CSTTornado WarningFSDWoodbury45 min
Dec 15, 4:17 PM CSTTornado WarningFSDPlymouth, Woodbury28 min
Dec 15, 4:26 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDPlymouth, Woodbury34 min
Dec 15, 4:31 PM CSTTornado WarningFSDIda, Plymouth, Woodbury29 min
Dec 15, 4:32 PM CSTTornado WarningFSDPlymouth, Woodbury28 min
Dec 15, 4:42 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay, Ida, O'Brien, Plymouth and 1 more33 min
Dec 15, 4:51 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDO'Brien, Sioux39 min
Dec 15, 4:56 PM CSTSevere Thunderstorm Warning Destructive damage threatFSDBuena Vista, Cherokee, Clay, Ida46 min
Dec 15, 5:08 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay37 min
Dec 15, 5:15 PM CSTTornado WarningFSDBuena Vista, Cherokee, Clay, O'Brien30 min
Dec 15, 5:29 PM CSTSevere Thunderstorm Warning Considerable damage threatFSDDickinson46 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021Every severe thunderstorm 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.