Alert archive / Iowa / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 122, NWS Des Moines, IA

December 15, 2021Carroll County, Crawford County, Sac County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Dec 15, 2021, 4:16 PM CST for Carroll County, Crawford County, Sac County, Iowa. It was in force for 74 min. 4 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, 4:16 PM CST (22:16 UTC)
Expired: Dec 15, 2021, 5:30 PM CST
In force: 74 min
Issued by: NWS Des Moines, IA
Area: Storm-based polygon
Tornado: Possible
Damage threat: Destructive
Hail: 0.75 in
Wind: 80.0 mph

Counties Carroll County, IA, Crawford County, IA, Sac County, IA

The radar

The Des Moines radar (KDMX), 137 km from the middle of the area, began a volume at 22:16 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
Dec 15, 4:55 PM CST	TSTM WND GST 81	4 Nne Buck Grove, IA	AWOS STATION KDNS DENISON AIRPORT.
Dec 15, 5:23 PM CST	HAIL 1	Coon Rapids, IA
Dec 15, 5:27 PM CST	TSTM WND GST 70	Coon Rapids, IA
Dec 15, 5:35 PM CST	TSTM WND DMG	3 S Glidden, IA	OUTBUILDING DESTROYED AT 240TH ST. AND TIMBER AVE. SIZE OF BUILDING UNKNOWN.

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.

Issued	Product	Office	Lasted
Dec 15, 1:23 PM CST	Tornado Watch	SPC	7 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.3 hours before the alert went out and 143 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: 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.

510 
WUUS53 KDMX 152216
SVRDMX
IAC027-047-161-152330-
/O.NEW.KDMX.SV.W.0122.211215T2216Z-211215T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Severe Thunderstorm Warning
National Weather Service Des Moines IA
416 PM CST Wed Dec 15 2021

The National Weather Service in Des Moines  has issued a

* Severe Thunderstorm Warning for...
  Sac County in west central Iowa...
  Crawford County in west central Iowa...
  Carroll County in west central Iowa...

* Until 530 PM CST.

* At 414 PM CST, severe thunderstorms were located along a line
  extending from near Salix to near Modale, moving northeast at 65
  mph.

  THESE ARE DESTRUCTIVE STORMS FOR WEST CENTRAL IOWA.

  HAZARD...80 mph wind gusts.

  SOURCE...Emergency management.

  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.

* Locations impacted include...
  Denison and Carroll.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for west central
Iowa.

This is an EXTREMELY DANGEROUS SITUATION with tornado like wind
speeds expected. Mobile homes and high profile vehicles are
especially susceptible to winds of this magnitude and may be
overturned. For your protection move to an interior room on the
lowest floor of a building. These storms have the potential to cause
serious injury and significant property damage.

A Tornado Watch remains in effect until 800 PM CST for west central
Iowa.

&&

LAT...LON 4221 9567 4221 9532 4247 9532 4248 9539
      4256 9539 4256 9493 4236 9486 4221 9486
      4221 9480 4186 9467 4187 9567
TIME...MOT...LOC 2214Z 232DEG 56KT 4233 9622 4156 9603 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Cogil

3 follow-up statements

575 
WWUS53 KDMX 152241
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
441 PM CST Wed Dec 15 2021

IAC027-047-161-152330-
/O.CON.KDMX.SV.W.0122.000000T0000Z-211215T2330Z/
Sac IA-Crawford IA-Carroll IA-
441 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CST
FOR SAC...CRAWFORD AND CARROLL COUNTIES...

At 440 PM CST, severe thunderstorms were located along a line
extending from near Washta to near Dunlap, moving east at 65 mph.

THESE ARE DESTRUCTIVE STORMS FOR WEST CENTRAL IOWA.

HAZARD...80 mph wind gusts.

SOURCE...Emergency management.

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.

Locations impacted include...
Carroll, Denison, Sac City, Manning, Coon Rapids, Lake View, Odebolt,
Black Hawk Lake, Schleswig, Wall Lake, Manilla, Schaller, Early, Dow
City, Charter Oak, Arcadia, Breda, Vail, Templeton and Auburn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for west central
Iowa.

This is an EXTREMELY DANGEROUS SITUATION with tornado like wind
speeds expected. Mobile homes and high profile vehicles are
especially susceptible to winds of this magnitude and may be
overturned. For your protection move to an interior room on the
lowest floor of a building. These storms have the potential to cause
serious injury and significant property damage.

&&

LAT...LON 4221 9567 4221 9532 4247 9532 4248 9539
      4256 9539 4256 9493 4236 9486 4221 9486
      4221 9480 4186 9467 4187 9567
TIME...MOT...LOC 2240Z 255DEG 55KT 4258 9579 4181 9561 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Cogil

324 
WWUS53 KDMX 152305
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
505 PM CST Wed Dec 15 2021

IAC027-047-161-152330-
/O.CON.KDMX.SV.W.0122.000000T0000Z-211215T2330Z/
Sac IA-Crawford IA-Carroll IA-
505 PM CST Wed Dec 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM CST
FOR SAC...CRAWFORD AND CARROLL COUNTIES...

At 504 PM CST, severe thunderstorms were located along a line
extending from near Aurelia to near Denison, moving east at 65 mph.

THESE ARE DESTRUCTIVE STORMS FOR WEST CEntral Iowa.

HAZARD...80 mph wind gusts.

SOURCE...Emergency management.

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.

Locations impacted include...
Carroll, Denison, Sac City, Manning, Coon Rapids, Lake View, Odebolt,
Black Hawk Lake, Schleswig, Wall Lake, Manilla, Schaller, Early,
Arcadia, Breda, Vail, Templeton, Auburn, Westside and Kiron.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 800 PM CST for west central
Iowa.

This is an EXTREMELY DANGEROUS SITUATION with tornado like wind
speeds expected. Mobile homes and high profile vehicles are
especially susceptible to winds of this magnitude and may be
overturned. For your protection move to an interior room on the
lowest floor of a building. These storms have the potential to cause
serious injury and significant property damage.

&&

LAT...LON 4221 9555 4221 9532 4247 9532 4248 9539
      4256 9539 4256 9493 4236 9486 4221 9486
      4221 9480 4186 9467 4187 9543
TIME...MOT...LOC 2304Z 270DEG 56KT 4279 9542 4202 9524 

TORNADO...POSSIBLE
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

Cogil

480 
WWUS53 KDMX 152334
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
534 PM CST Wed Dec 15 2021

IAC027-047-161-152343-
/O.EXP.KDMX.SV.W.0122.000000T0000Z-211215T2330Z/
Sac IA-Crawford IA-Carroll IA-
534 PM CST Wed Dec 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR SAC...CRAWFORD AND CARROLL
COUNTIES HAS EXPIRED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been allowed to expire.

A Tornado Watch remains in effect until 800 PM CST for west central
Iowa.

LAT...LON 4221 9555 4221 9532 4247 9532 4248 9539
      4256 9539 4256 9493 4236 9486 4221 9486
      4221 9480 4186 9467 4187 9543
TIME...MOT...LOC 2333Z 232DEG 56KT 4306 9495 4229 9478 

$$

Cogil

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 15, 4:13 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Adair, Adams, Audubon, Cass, Guthrie, Ringgold and 2 more	77 min
Dec 15, 4:37 PM CST	Tornado Warning Tornado observed	DMX	Cass	23 min
Dec 15, 4:44 PM CST	Tornado Warning	DMX	Crawford	36 min
Dec 15, 4:53 PM CST	Tornado Warning	DMX	Adair, Audubon, Cass, Guthrie	33 min
Dec 15, 5:07 PM CST	Tornado Warning	DMX	Sac	27 min
Dec 15, 5:10 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Adair, Audubon, Boone, Dallas, Greene, Guthrie and 4 more	80 min
Dec 15, 5:10 PM CST	Tornado Warning	DMX	Carroll, Crawford	35 min
Dec 15, 5:14 PM CST	Tornado Warning	DMX	Audubon, Calhoun, Carroll, Greene, Guthrie	31 min
Dec 15, 5:15 PM CST	Tornado Warning	DMX	Calhoun, Carroll, Crawford, Sac	30 min
Dec 15, 5:18 PM CST	Tornado Warning Tornado observed	DMX	Adair, Boone, Dallas, Greene, Guthrie	42 min
Dec 15, 5:19 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Boone, Calhoun, Carroll, Emmet, Greene, Humboldt and 5 more	71 min
Dec 15, 5:22 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Carroll, Crawford, Sac	23 min
Dec 15, 5:22 PM CST	Severe Thunderstorm Warning Considerable damage threat	DMX	Adair, Adams, Clarke, Decatur, Madison, Ringgold and 3 more	68 min
Dec 15, 5:36 PM CST	Tornado Warning	DMX	Calhoun, Humboldt, Kossuth, Palo Alto, Pocahontas	24 min
Dec 15, 5:38 PM CST	Tornado Warning Tornado observed	DMX	Boone, Calhoun, Greene, Hamilton, Webster	37 min
Dec 15, 5:45 PM CST	Tornado Warning	DMX	Calhoun, Pocahontas, Webster	30 min
Dec 15, 5:52 PM CST	Severe Thunderstorm Warning Destructive damage threat	DMX	Boone, Franklin, Hamilton, Hancock, Hardin, Humboldt and 6 more	53 min
Dec 15, 5:58 PM CST	Tornado Warning	DMX	Hancock, Humboldt, Kossuth, Palo Alto, Pocahontas	32 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2021 Every 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.