Severe Storms and Extreme Winds - December 15, 2021

Tornadoes

Tornado #1 - SW of Kenwood Denison County Date December 15, 2021 Time (Local) 4:48pm - 4:51pm EF Rating EF-Unknown Est. Peak Winds Unknown Path Length 4.40 miles Max Width 50 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #2 - Atlantic to Hamlin Cass and Audubon Counties, IA Date December 15, 2021 Time (Local) 4:49pm-5:09pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 27.2 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Barn with roof missing west of Atlantic​ ​Credit: NWS Des Moines Metal transmission poles bent over near base north of Atlantic​ ​Credit: NWS Des Moines Outbuilding destroyed north of Atlantic​ ​Credit: NWS Des Moines 3 transmission poles snapped north of Atlantic​ ​Credit: NWS Des Moines

Animation of the storm relative velocity as the tornado developed just southwest of Atlantic (4:50 p.m. CT) and then it quickly moved northeast causing EF-2 damage. Still image of storm relative velocity signature at 4:50 p.m. CT when the tornado developed.  Correlation coefficient suggesting some debris being lofted just west of Atlantic about 5 minutes after the tornado initially developed. Base velocity (0.5°) showing the intense rotational couplet on west part of Atlantic at 4:53 p.m. CT

Tornado #3 - South and East of Exira Cass and Audubon Counties Date December 15, 2021 Time (Local) 5:00pm - 5:09pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 11.8 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Garage building destroyed east of Exira. Credit: Sarah McGinnis Pavilion destroyed east of Exira. Credit: Sarah McGinnis

Tornado #4 - West of Guthrie Center Guthrie County Date December 15, 2021 Time (Local) 5:10pm - 5:18pm EF Rating EF-1 Est. Peak Winds 90-100 Path Length 11.5 miles Max Width 70 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Damage on farmstead west of Guthrie Center. Credit: Bradford Family Damage on farmstead west of Guthrie Center. Credit: Bradford Family

Tornado #5 - West of Breda to Lytton Carroll and Sac Counties Date December 15, 2021 Time (Local) 5:13pm-5:26pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 17.7 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Farm outbuilding destroyed and some siding ripped off home near Carnarvon ​Credit: NWS Des Moines Destruction of farm outbuilding southeast of Black Hawk Lake ​​Credit: NWS Des Moines Destruction of farm outbuilding southeast of Black Hawk Lake ​​Credit: NWS Des Moines Outbuilding destruction near Carnarvon ​​Credit: NWS Des Moines Storm relative velocity as the tornado develops south-southeast of Wall Lake (5:13 p.m. CT) and then it quickly moved northeast. Damage rating at this point was EF-0 and EF-1. Storm relative velocity as the tornado is east of Wall Lake and recently producing EF-2 damage (5:17 p.m. CT). Storm relative velocity shortly after the tornado crossed Hwy 175 east of Lake View (5:21 p.m. CT) Additional EF-2 damage occurred around this time. Storm relative velocity as the tornado nears its end near Lytton (5:24 p.m. CT).

Tornado #6 - Bayard Guthrie and Greene Counties, IA Date December 15, 2021 Time (Local) 5:14pm-5:28pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 19.7 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

EF-2 damage to home in Bayard, Iowa. Credit: NWS storm survey. Storm relative velocity loop of the Bayard Tornado. Damage path is the yellow line. A second weaker tornado track is shown just west of the main tornado path.   2322 UTC (5:22 p.m. CT) Base velocity (right) and storm-relative velocity (left) showing the tight circulation near Bayard. Tornado path is yellow line.  2324 UTC (5:24 p.m. CT) Base velocity (right) and storm-relative velocity (left) showing the tight rotation over Bayard. Tornado path is yellow line.

Tornado #7 - Between Carroll and Glidden Carroll County Date December 15, 2021 Time (Local) 5:19pm - 5:26pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 9.7 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Caption Caption Caption Caption

Tornado #8 - Springbrook to Bagley, Jefferson, and Paton Guthrie and Greene Counties, IA Date December 15, 2021 Time (Local) 5:21pm-5:42pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 30.1 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Radar loop of storm Credit: NWS Damage Survey 2327 UTC

Tornado #9 - Bagley to Grand Junction to east of Dana Guthrie and Greene Counties Date December 15, 2021 Time (Local) 5:27pm - 5:45pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 23.5 miles Max Width 100 Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Power pole snapped northwest of Herndon ​Credit: NWS Des Moines Tree on house south side of Grand Junction ​Credit: NWS Des Moines

Tornado #10 - SW of Jefferson Greene County Date December 15, 2021 Time (Local) 5:29pm - 5:33pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 5.5 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey

Tornado #11 - Far W of Jefferson Greene County Date December 15, 2021 Time (Local) 5:32pm - 5:36pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 5.9 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Credit: NWS Damage Survey Credit: NWS Damage Survey

Tornado #12 - South of Churdan Greene County Date December 15, 2021 Time (Local) 5:34pm - 5:36pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 2.7 miles Max Width 70 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

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Tornado #13 - East of Lake City Calhoun County Date December 15, 2021 Time (Local) 5:34pm - 5:35pm EF Rating EF-Unknown Est. Peak Winds Unknown Path Length 1.33 miles Max Width 40 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #14 - Lohrville to Knierim Calhoun County Date December 15, 2021 Time (Local) 5:35pm - 5:49pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 19.2 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Damaged grain bin pushed into field near Lohrville. Credit: Calhoun County Emergency Management Grain bin base of bin that was pushed into field near Lohrville. Credit: Calhoun County Emergency Management Tree and sheet metal damage near Knierim. Credit: Calhoun County Emergency Management 2344 UTC (5:44 p.m. CT) showing twin circulations on radar via storm relative velocity.. Tornado tracks overlaid  Loop of the Knierim and Somers tornadoes. Left image is storm relative velocity and right in correlation coefficient which shows some damage being lofted (some of the blue pixels)

Tornado #15 - East of Grand Junction to Dayton Greene, Boone, and Webster Counties Date December 15, 2021 Time (Local) 5:39pm - 5:52pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 17.7 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Tree limbs on a home near Dayton. Credit: Dayton Fire/Webster County Emergency Management Tree limbs that punctured into the same home near Dayton. Credit: Dayton Fire/Webster County Emergency Management Metal roofing removed from outbuilding near Dayton. Credit: Dayton Fire/Webster County Emergency Management

Tornado #16 - South of Somers to Barnum Calhoun and Webster Counties, IA Date December 15, 2021 Time (Local) 5:40pm - 5:54pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 18.0 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Power pole damage southeast of Rinard. Credit: Calhoun County Emergency Management Metal outbuilding damage near Rinard. Credit: Calhoun County Emergency Management Tree damage in Somers. Credit: Calhoun County Emergency Management Metal outbuilding significantly damaged near Somers. Credit: Calhoun County Emergency Management Tree snapped near base in Barnum. Credit: Webster County Emergency Management Tree damage in Barnum along the railroad tracks. Credit: Webster County Emergency Management

Tornado #17 - Ayrshire to Graettinger Palo Alto County Date December 15, 2021 Time (Local) 5:41pm - 5:51pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 11.2 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

2x4 into roof. Credit: Greta Rouse Partial roof torn and damage to wall of outbuildlng. Credit: Greta Rouse Garage door failure and roof uplift. Credit: Greta Rouse Garage door failure and wall blown out. Credit: Greta Rouse

Tornado #18 - SW of Paton to NW of Lehigh Greene and Webster Counties, IA Date December 15, 2021 Time (Local) 5:42pm-5:57pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 18.9 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

One of eight snapped power poles north of Burnside ​Credit: NWS Des Moines Damage to farm outbuilding southwest of Burnside ​Credit: NWS Des Moines Destruction of farm outbuilding near Harcourt ​Credit: NWS Des Moines Grain bin damage in far southern Webster County ​Credit: Gowrie Police Department/Webster County Emergency Management Outbuilding damage in far southern Webster County. ​Credit: Gowrie Police Department/Webster County Emergency Management Tree damage in far southern Webster County. ​Credit: Gowrie Police Department/Webster County Emergency Management Tree snapped and uprooted west of Lehigh. ​Credit: Lehigh Fire/Webster County Emergency Management Outbuilding damage west of Lehigh. ​Credit: Lehigh Fire/Webster County Emergency Management

Tornado #19 - Southeast of Palmer Pocahontas County Date December 15, 2021 Time (Local) 5:43pm - 5:44pm EF Rating EF-Unknown Est. Peak Winds Unknown Path Length 1.2 miles Max Width 40 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #20 - Near Pilot Mound to NW of Stanhope Boone, Webster, and Hamilton Counties Date December 15, 2021 Time (Local) 5:49pm - 6:01pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 16.3 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Hog building destroyed northeast of Stratford. Credit: Hamilton County Emergency Management Farm outbuilding partial roof removed. Credit: Hamilton County Emergency Management

Tornado #21 - West of Gilmore City Pocahontas and Humboldt Counties Date December 15, 2021 Time (Local) 5:50pm - 5:56pm EF Rating EF-Unknown Est. Peak Winds Unknown Path Length 7.11 miles Max Width 80 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #22 - Near Stratford to W of Kamrar Webster and Hamilton Counties Date December 15, 2021 Time (Local) 5:55pm-6:05pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 12.2 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map   Downloadable KMZ File

Total destruction of outbuilding northwest of Stanhope ​​Credit: NWS Des Moines Leaning power pole northeast of Stratford ​​Credit: NWS Des Moines Tree damage northeast of Stratford ​​Credit: NWS Des Moines Shingles removed and tree damage northeast of Stratford. Credit: Hamilton County Emergency Management 2x4 sticking out of farm outbuilding. ​​Credit: Hamilton County Emergency Management

Tornado #23 - North of Rutland Humboldt County Date December 15, 2021 Time (Local) 5:58pm - 6:01pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 4.2 miles Max Width 80 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

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Tornado #24 - West of Duncombe Webster County Date December 15, 2021 Time (Local) 6:00pm - 6:04pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 5.6 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Shingle loss east of Coalville near the start of the tornado track. Credit: Otho Fire/Webster County Emergency Management Damaged grain bins north of Highway 20. Credit: Duncombe Fire/Webster County Emergency Management Severely damaged outbuilding north of Highway 20. Credit: Duncombe Fire/Webster County Emergency Management

Tornado #25 - East to Northeast of Stanhope Hamilton County Date December 15, 2021 Time (Local) 6:01pm - 6:08pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 8.9 miles Max Width 70 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #26 - West of Webster City Webster and Hamilton Counties Date December 15, 2021 Time (Local) 6:01pm - 6:07pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 7.6 miles Max Width 80 Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #27 - West of Galt Wright County Date December 15, 2021 Time (Local) 6:19pm - 6:23pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 5.9 miles Max Width 70 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey

Tornado #28 - Rowan to NE of Meservey Wright, Franklin, and Cerro Gordo Counties Date December 15, 2021 Time (Local) 6:25pm-6:38pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 16.8 miles Max Width 100 Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Grain bin damaged southwest of Galt Credit: NWS Des Moines Tree damage just northeast of Merservey​ Credit: NWS Des Moines

Tornado #29 - Alden to Bradford Hardin and Franklin Counties Date December 15, 2021 Time (Local) 6:26pm - 6:35pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 13.0 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

​Credit: Franklin County Emergency Management

Tornado #30 - Iowa Falls to Dumont Hardin and Franklin Counties Date December 15, 2021 Time (Local) 6:27pm - 6:43pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 22.2 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

​Farm building damaged east southeast of Geneva. Credit: Franklin County Emergency Management Outbuilding damage east of Geneva. ​Credit: Franklin County Emergency Management Tree and farm outbuilding damage east southeast of Geneva. Credit: Franklin County Emergency Management Debris field downstream into fields  from a farmstead east south of Geneva. Credit: Franklin County Emergency Management

Tornado #31 - East of Kanawha Wright and Hancock Counties Date December 15, 2021 Time (Local) 6:28pm - 6:32pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 5.2 miles Max Width 60 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #32 - Chapin to Sheffield Franklin County Date December 15, 2021 Time (Local) 6:38pm - 6:43pm  EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 6.0 miles Max Width 80 yds Injuries/Deaths 0/0 A Union Pacific weather station near Chapin recorded a 108 mph unofficial wind gust as the tornadic circulation passed near the site. Track Map Downloadable KMZ File

Outbuilding significantly damaged just east of Sheffield off Highway 65. Credit: Jared Rowe Grain bin damaged. Credit: Jared Rowe Damage east of Sheffield. Credit: Jared Rowe Damage east of Sheffield. Credit: Jared Rowe Drone image of damage just east of Sheffield off Highway 65. Credit: Franklin County Emergency Management Tree damage near the start of the Chapin-Sheffield tornado. Credit: Franklin County Emergency Management Tree damage near Chapin. Credit: Franklin County Emergency Management

Tornado #33 - Southeast of Hansell Franklin County Date December 15, 2021 Time (Local) 6:40pm - 6:46pm EF Rating EF-2 Est. Peak Winds 115-120 mph Path Length 7.6 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey Credit: NWS Damage Survey Credit: NWS Damage Survey Outbuilding roof removal and debris field downstream into fields. Credit: Franklin County Emergency Management

Tornado #34 - East of Rockwell Cerro Gordo County Date December 15, 2022 Time (Local) 6:44pm - 6:46pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 2.9 mph Max Width 40 mph Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #35 - West of Scarville Winnebago and Faribault Counties Date December 15, 2021 Time (Local) 6:48pm - 6:50 pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 2.9 miles Max Width 90 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Credit: NWS Damage Survey (MPX) Credit: NWS Damage Survey (MPX)

Tornado #36 - West of Greene Butler and Floyd Counties Date December 15, 2021 Time (Local) 6:53pm - 6:57pm EF Rating EF-1 Est. Peak Winds 90-100 mph Path Length 4.2 miles Max Width 100 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

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Tornado #37 - Northeast of Rock Falls Cerro Gordo Date December 15, 2021 Time (Local) 6:54pm - 6:57pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 3.6 miles Max Width 60 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado #38 - Kensett to Northwood Worth County Date December 15, 2021 Time (Local) 6:58pm - 7:05pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 9.1 miles Max Width 80 yds Injuries/Deaths 0/0 Track Map Downloadable KMZ File

Damage to a trailer house in Northwood. Credit: Worth County Emergency Management Damage to a trailer house in Northwood. Credit: Worth County Emergency Management Power poles snapped in central Worth County. Credit: Worth County Emergency Management

Tornado #39 - Southeast of Newton Jasper County Date December 15, 2021 Time (Local) 7:03pm - 7:05pm EF Rating EF-Unknown Est. Peak Winds TBD Path Length 2.0 miles Max Width TBD Injuries/Deaths 0/0 Track Map Downloadable KMZ File

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Tornado #40 - Northeast of Northwood Worth, Freeborn, and Mower Counties Date December 15, 2021 Time (Local) 7:10pm - 7:12pm EF Rating EF-0 Est. Peak Winds 65-85 mph Path Length 2.6 miles Max Width 50 yds Injuries/Deaths 0/0 Tornado occurrence was identified using satellite and/or radar analysis. Track Map Downloadable KMZ File

Tornado - LOCATION COUNTY NAME Date   Time (Local)   EF Rating   Est. Peak Winds   Path Length   Max Width   Injuries/Deaths   Summary: Short summary of the tornado. Track Map Downloadable KMZ File

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Tornado - LOCATION COUNTY NAME Date   Time (Local)   EF Rating   Est. Peak Winds   Path Length   Max Width   Injuries/Deaths   Summary: Short summary of the tornado. Track Map Downloadable KMZ File

Caption Caption Caption Caption

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Storm Reports

Click map below to go to an interactive webpage or see below for a text summary of storm reports across Iowa.

Storm Reports across Iowa December 15, 2021 3pm to December 16, 2021 6am

Reports - Wind Gusts Greater Than or Equal to 58 mph

• Non-Thunderstorm Wind Gusts
• Thunderstorm Wind Gusts

Non-Thunderstorm Wind Gusts greater than or equal to 58 mph after the cold front passed

Public Information Statement
National Weather Service Des Moines IA
410 PM CST Sat Dec 18 2021

...December 15-16, 2021 Non-Thunderstorm Wind Gusts
Greater than or Equal to 58 mph Behind the Cold Front...

Location                     Speed     Time/Date       Lat/Lon
Decatur City                 83 MPH    1000 PM 12/15   40.74N/93.84W
Marshalltown Airport         81 MPH    1039 PM 12/15   42.12N/92.92W
1 WNW Johnston               80 MPH    0830 PM 12/15   41.68N/93.75W
2 N Hanlontown               78 MPH    0850 PM 12/15   43.31N/93.38W
Lamoni Airport               77 MPH    0815 PM 12/15   40.63N/93.90W
Mason City Airport           75 MPH    1242 AM 12/16   43.15N/93.33W
Des Moines Int Airport (DSM) 74 MPH    0823 PM 12/15   41.53N/93.67W
Des Moines Int Airport (DSM) 71 MPH    0815 PM 12/15   41.53N/93.65W
Lamoni Airport               70 MPH    0750 PM 12/15   40.63N/93.90W
1 NE Bedford - Hwy 2         68 MPH    0710 PM 12/15   40.68N/94.71W
3 E Creston - Hwy 34         67 MPH    0810 PM 12/15   41.05N/94.31W
Ames Airport                 67 MPH    1005 PM 12/15   41.99N/93.62W
Estherville Airport          67 MPH    1241 AM 12/16   43.40N/94.75W
2 WNW Gruver                 67 MPH    1254 AM 12/16   43.41N/94.75W
Creston Airport              66 MPH    0735 PM 12/15   41.02N/94.37W
3 E Creston - Hwy 34         66 MPH    0740 PM 12/15   41.05N/94.31W
Algona Airport               66 MPH    0935 PM 12/15   43.07N/94.27W
2 W Evansdale                65 MPH    1140 PM 12/15   42.46N/92.31W
3 WNW Gruver                 64 MPH    1158 PM 12/15   43.41N/94.75W
Boone Airport                64 MPH    0955 PM 12/15   42.03N/93.83W
Algona Airport               63 MPH    1055 PM 12/15   43.08N/94.27W
Osceola Airport              63 MPH    0815 PM 12/15   41.05N/93.68W
Carroll Airport              63 MPH    0915 PM 12/15   42.03N/94.77W
Ottumwa                      62 MPH    1055 PM 12/15   41.00N/92.44W
1 NE Bedford - Hwy 2         62 MPH    0720 PM 12/15   40.68N/94.71W
Ankeny Airport               62 MPH    0835 PM 12/15   41.68N/93.57W
Chariton Airport             62 MPH    0855 PM 12/15   41.02N/93.37W
Waterloo Airport             62 MPH    1117 PM 12/15   42.55N/92.40W
Blockton                     61 MPH    0730 PM 12/15   40.62N/94.47W
6.3 SW Albion (UPR)          61 MPH    1034 PM 12/15   42.03N/93.04W
2 WNW Gruver                 61 MPH    0114 AM 12/16   43.41N/94.75W
Perry Airport                61 MPH    0955 PM 12/15   41.83N/94.16W
Mason City Airport           61 MPH    1238 AM 12/16   43.16N/93.33W
Ames Airport                 60 MPH    0817 PM 12/15   41.99N/93.62W
Altoona                      60 MPH    1045 PM 12/15   41.63N/93.47W
Marshalltown Airport         60 MPH    0857 PM 12/15   42.11N/92.92W
Algona Airport               60 MPH    1035 PM 12/15   43.08N/94.27W
2 SW Hampton                 60 MPH    1158 PM 12/15   42.72N/93.23W
Hampton Airport              60 MPH    1235 AM 12/16   42.58N/93.23W
2 WNW Gruver                 60 MPH    0918 PM 12/15   43.41N/94.75W
Waterloo Airport             60 MPH    1258 AM 12/16   42.56N/92.40W
Creston Airport              59 MPH    0915 PM 12/15   41.02N/94.36W
2 E Ames                     59 MPH    1010 PM 12/15   42.03N/93.57W
0.6 W Elkhart (UPR)          59 MPH    0833 PM 12/15   41.79N/93.53W
Des Moines Int Airport (DSM) 59 MPH    1154 PM 12/15   41.54N/93.66W
Marshalltown (US 30)         59 MPH    1053 PM 12/15   42.00N/92.96W
Algona Airport               59 MPH    1158 PM 12/15   43.08N/94.27W
Hampton Airport              59 MPH    0100 AM 12/16   42.73N/93.23W
Waterloo                     59 MPH    1105 PM 12/15   42.47N/92.42W
3 NNW Pleasant Hill          58 MPH    1059 PM 12/15   41.63N/93.53W
Iowa Falls Airport           58 MPH    1035 PM 12/15   42.47N/93.27W
Hampton Airport              58 MPH    1055 PM 12/15   42.72N/93.23W
Perry Airport                58 MPH    0755 PM 12/15   41.83N/94.17W
Waterloo Airport             58 MPH    1037 PM 12/15   42.56N/92.40W

Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.

Thunderstorm Wind Gusts greater than or equal to 58 mph after the cold front passed

Public Information Statement
National Weather Service Des Moines IA
445 PM CST Thu Dec 16 2021

...December 15, 2021 Thunderstorm Wind Gusts Greater than or Equal
to 58 mph...

Location                     Speed     Time/Date       Lat/Lon
Audubon                      88 MPH    0511 PM 12/15   41.72N/94.93W
3 NE Clear Lake              83 MPH    0653 PM 12/15   43.16N/93.33W
4 SE Kirkville               82 MPH    0754 PM 12/15   41.11N/92.45W
Denison Airport              81 MPH    0455 PM 12/15   41.97N/95.37W
2 S Adair                    80 MPH    0515 PM 12/15   41.48N/94.64W
3 W Dallas Center            80 MPH    0549 PM 12/15   41.69N/94.02W
Adair                        76 MPH    0512 PM 12/15   41.50N/94.64W
3 SW Minburn                 75 MPH    0545 PM 12/15   41.73N/94.07W
1 WNW Johnston               75 MPH    0627 PM 12/15   41.68N/93.75W
3 ESE Dawson                 74 MPH    0545 PM 12/15   41.83N/94.16W
4 NE Guthrie Center          73 MPH    0525 PM 12/15   41.72N/94.46W
4 S Scranton                 73 MPH    0527 PM 12/15   41.96N/94.55W
3 NNW Fort Dodge             73 MPH    0602 PM 12/15   42.55N/94.19W
Coon Rapids                  70 MPH    0527 PM 12/15   41.87N/94.68W
Ralston                      70 MPH    0531 PM 12/15   42.04N/94.64W
Perry                        70 MPH    0541 PM 12/15   41.84N/94.10W
Minburn                      70 MPH    0541 PM 12/15   41.76N/94.03W
3 S Creston                  70 MPH    0555 PM 12/15   41.02N/94.36W
Gilbert                      70 MPH    0613 PM 12/15   42.11N/93.65W
2 W Algona                   70 MPH    0615 PM 12/15   43.08N/94.27W
3 ESE Adel                   70 MPH    0617 PM 12/15   41.60N/93.98W
Indianola                    70 MPH    0637 PM 12/15   41.36N/93.57W
Oskaloosa                    70 MPH    0716 PM 12/15   41.29N/92.64W
2 N Winterset                68 MPH    0619 PM 12/15   41.36N/94.02W
2 WNW Algona                 67 MPH    0615 PM 12/15   43.08N/94.27W
2 ENE Lamoni                 67 MPH    0625 PM 12/15   40.63N/93.90W
8 W Guthrie Center           65 MPH    0517 PM 12/15   41.67N/94.65W
1 WNW Johnston               65 MPH    0607 PM 12/15   41.68N/93.75W
Centerville                  65 MPH    0727 PM 12/15   40.73N/92.87W
1 NW Hampton                 64 MPH    0638 PM 12/15   42.76N/93.21W
3 W Chariton                 64 MPH    0648 PM 12/15   41.02N/93.36W
Knoxville Airport            64 MPH    0655 PM 12/15   41.28N/93.12W
Neil Smith NWR               64 MPH    0731 PM 12/15   41.57N/93.26W
Linden                       62 MPH    0539 PM 12/15   41.64N/94.27W
2 W Algona                   62 MPH    0615 PM 12/15   43.08N/94.27W
Waterloo Regional Airport (A 62 MPH    0736 PM 12/15   42.56N/92.40W
Waterloo Regional Airport (A 62 MPH    0736 PM 12/15   42.56N/92.40W
Des Moines Int Airport (DSM) 61 MPH    0627 PM 12/15   41.53N/93.66W
Des Moines Int Airport (DSM) 61 MPH    0627 PM 12/15   41.53N/93.66W
Waterloo Regional Airport (A 61 MPH    0734 PM 12/15   42.56N/92.40W
Waterloo Regional Airport (A 61 MPH    0734 PM 12/15   42.56N/92.40W
2 ENE Lamoni                 60 MPH    0527 PM 12/15   40.63N/93.90W
5 ENE Osceola                60 MPH    0629 PM 12/15   41.05N/93.69W
Ankeny Airport               60 MPH    0635 PM 12/15   41.68N/93.57W
2 WSW Pella                  60 MPH    0715 PM 12/15   41.40N/92.95W
3 WNW Fremont                60 MPH    0752 PM 12/15   41.22N/92.49W
2 S Ames                     58 MPH    0608 PM 12/15   41.99N/93.62W

Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.

Radar/Satellite

Slow Multi-Radar Multi-Sensor (MRMS) animation of the thunderstorms/derecho moving through Iowa on December 15, 2021.

Radar loop of the thunderstorms/derecho moving through Iowa on December 15, 2021. Courtesy of the Iowa Environmental Mesonet.

GOES-East Water Vapor Imagery courtesy of NWS Chicago event webpage.

SATELLITE BLOG DISUCSSIONS

• Derecho Sweeps Across Midwest (NASA Earth Observatory)
• December 10, 2021 Snow, Dust, and Thunderstorms (Satellite Liaison Blog)
• Blowing dust aided by a sting jet across the central Plains (CIMSS Satellite Blog)
• Mid-December 2021 Blowing Dust (Satellite Liaison Blog)

Environment

Below are some animations and still images of the synoptic environment throughout the day Wednesday, December 15 and into Thursday, December 16, 2021. Tremendous about of shear and helicity was present with the cold front sweep across the region.  This lead to multiple tornadoes that occurred over Nebraska, Iowa, Minnesota, and Wisconsin. 

Figure 1: OAX 00z Sounding samples the very little CAPE present but the tremendous amount of shear available. Note, this was launched just after convection rolled through eastern NE.	Figure 2: Observed Topeka soundings at 12z, 18z, and 00z (16th).  The special launch showed a considerable increase in the instability since the morning sounding. The shear values, particularly the deep layer shear increased and winds began to veer with heights.	Figure 3: Observed Davenport soundings at 12z and 00z (16th).  The 00z soundings showed very high values of Storm-relative helicity, strong shear throughout the column, enough low level CAPE, and veering winds. All significant for tornadic development.

Near-storm Environment Summary

Figure 4: Loop of the 3-km CAPE (J/kg) & Surface Vorticity. CAPE in the lowest 3-km above ground level, and surface relative vorticity.  Areas of large 0-3-km CAPE tend to favor strong low-level stretching, and can support tornado formation when co-located with significant vertical vorticity near the ground.	Figure 5: Surface to 1-km shear vector (kts).   Surface-1-km Vertical Shear is the difference between the surface wind and the wind at 1-km above ground level. These data are plotted as vectors with shear magnitudes contoured. 0-1-km shear magnitudes greater than 15-20 knots tend to favor supercell tornadoes.	Figure 6: Significant Tornado Parameter (fixed layer) includes a combination of several other parameters. It includes the 0-6 km bulk wind difference, 0-1 km storm-relative helicity, surface parcel CAPE, and surface parcel LCL height. A STP greater than 1 typically have been associated to EF-2 or greater damage.

Figure 7: The Storm Relative Helicity (m2/s2) and is a measure of the potential for cyclonic updraft rotation in right-moving supercells, and is calculated for the lowest 1-km and 3-km layers above ground level. Larger values of 0-3-km SRH (greater than 250 m2 s-2) and 0-1-km SRH (greater than 100 m2 s-2), however, do suggest an increased threat of tornadoes with supercells. For SRH, larger values are generally better, but there are no clear thresholds between non-tornadic and significant tornadic supercells.	Figure 8: Caption	Figure 9: pressure change over time showing the amazing pressure falls then rises after the cold front.  The sharp rises in pressure are related to very strong winds.

Surface and Upper Air Analysis

Figure 10: Surface analysis every 3 hours beginning Tuesday night, December 14th and ending Thursday morning, December 16th. Shows the rapid strengthening of the surface low as it moves across the Central Plains.	Figure 11: 925mb upper air analysis is great for showing low level moisture advection and strong winds near the surface.	Figure 12: 850mb similar usage to the 925mb showing strong LLJ and moisture advection into the region. Plus the deepening/stacking of the low pressure system.

Figure 13: 700mb, another low level chart showing the massive deepening of the low pressure system and the isobars becoming closed by 00z on the 16th.	Figure 14: The 500mb upper air chart captures the rapid height falls and the negative tilt of the trough in eastern Nebraska/eastern Kansas. This is an indication of strong vertical wind shear, the low is near maturity, and differential advection (increases instability).	Figure 15: 300mb level chart shows the stacking of the low pressure system with the negative tilt of the trough. This shows the very strong jet placing Iowa in the left exit region which is an indication of strong vertical motion and upper level divergence.

SPC Severe Weather Event: December 15, 2021

Temperatures and Wind Records

Daily Record Highs Broken

All-Time December Record Highs Broken

*Additional years had the old record; most recent occurrence shown

All-Time December State Record High - Preliminarily Broken

Highest Non-Thunderstorm Wind Gust

Impacts

Iowa's Past Derechos

A listing of past derechos that have impacted at least some portion of Iowa since mainly 1980. The name in quotes is taken from the "Noteworthy Events" from the Storm Prediction Center's "About Derechos" webpage with the exception of the 1877 and 2020 derecho. Click on the link(s) below the image for additional details from the Storm Prediction Center's summary, an event webpage, and/or a journal article.

July 31, 1877 - "The Original Derecho" Image by Hinrichs (1888)	July 4-5, 1980 Derecho - "The 'More Trees Down' Derecho" Image courtesy of Storm Prediction Center	July 19, 1983 Derecho - "The I-94 Derecho" Image courtesy of Storm Prediction Center

July 28-29, 1986 Derecho - "The Supercell Transition Derecho" Image courtesy of Storm Prediction Center	July 7-8, 1991 Derecho - "The Southern Great Lakes Derecho of 1991" Image courtesy of Storm Prediction Center	July 8-9, 1993 Derecho - "The Great Plains Derecho" Image by Bentley and Cooper (1997)

May 30-31, 1998 Derecho - "The Southern Great Lakes Derecho of 1998" Image courtesy of Storm Prediction Center	June 29, 1998 - "The Corn Belt Derecho" Image courtesy of Storm Prediction Center June 29, 1998 Central Iowa Tornado/Derecho Event - WFO Des Moines Summary	July 20, 2008 WFO Quad Cities Summary

July 11, 2011 - "The Cross Country Derecho of July 2011" Image courtesy of Storm Prediction Center July 11, 2011 East Central Iowa Derecho - WFO Des Moines Event Summary Webpage	June 30, 2014 - "The One-Two Punch Derechos" Image courtesy of Storm Prediction Center June 30, 2014 Severe Weather Outbreak - WFO Des Moines Event Summary Webpage	August 10, 2020 - "The August 2020 Midwest Derecho" August 10, 2020 Derecho - WFO Des Moines Event Summary Webpage

December 15, 2021 - "December Serial Derecho" December 15, 2021 - WFO Des Moines Event Summary Webpage

Derechos Facts & FAQs