Des Moines, IA

Weather Forecast Office

August 10, 2020 Derecho

Overview

Widespread, destructive straight line winds blew across central Iowa during the day on August 10, 2020. The highest official wind gusts measured was 99 mph at the Marshalltown Airport with an unofficial wind gust of 106 mph at Le Grand (east of Marshalltown). The strongest winds were between the Highway 30 and Interstate 80 corridor (including, but not limited to the Des Moines metro, Ames, Newton, Marshalltown, Tama/Toledo, Carroll) from central Iowa eastward into east central Iowa and northern Illinois. Last update: March 30, 2022 4:46 a.m. CDT

StoryMap - August 10, 2020 Midwest Derecho

Other NWS Office Event Summaries:

NWS Quad Cities | NWS Chicago | NWS Milwaukee

NWS Central Illinois | NWS Northern Indiana | NWS Indianapolis

Wind Gusts Greater than 70 mph in NWS Des Moines' area of responsibility

Location	Wind Gust (mph)	Source
2 WNW Le Grand	106	Personal Weather Station
Marshalltown Airport	99	ASOS
2 S Marshalltown	95 (Estimated)	Storm Chaser
Marshalltown (US 30)	91	Iowa DOT
3 S Chelsea	90 (Estimated)	Trained Spotter
0.6 W Elkhart (UPR)	85	Mesowest
1 W Urbandale	85	Personal Weather Station
Neil Smith NWR	85	RAWS
2 ESE Jefferson	83	Personal Weather Station
1 N Des Moines Int Airport	80 (Estimated)	Trained Spotter
Colfax	80 (Estimated)	Public
Ankeny Airport	78	AWOS
2 ENE Saylorville	77 (Estimated)	Personal Weather Station
Hubbard	77	CWOP
Des Moines Int'l Airport	75	ASOS
2 SW Conrad	75 (Estimated)	Trained Spotter
Leighton	75	Personal Weather Station
5 WSW Cumming	75 (Estimated)	Trained Spotter
3 WSW Glidden	74	AWOS
Knoxville Airport	71	AWOS

Wind damaged grain bin in Tama County. Courtesy of Kip Ladage

Corn damaged near Adel. Courtesy of Lisa Schmitz

Video from Huxley, Iowa. Courtesy Jeff Wood


942am Des Moines Radar	1046am Des Moines Radar	1158am Des Moines Radar

Derecho Overview
Photos
Videos
Radar/Satellite
Storm Reports
Tornadoes
Environment
Iowa's Past Derechos
Derechos Facts/FAQs

Derecho Overview

Overview images of the swath of damage and power outages from the derecho and the progression of the derecho on Monday, August 10, 2020.

Preliminary map of the estimated winds across central to eastern Iowa. There were to distinct locations of 100+mph winds with the area near Cedar Rapids estimating gusts of 120+mph! This map combines both NWS Des Moines and NWS Quad Cities service areas. Last updated 8/25/2020 4:15 a.m. CDT. KMZ available here - this is preliminary and subject to change.

Preliminary map above shows the estimated wind speeds of the August 10, 2020 derecho across the region as of August 21, 2020. This is a collaborative effort between weather forecast offices Des Moines, IA Sioux Falls, SD Omaha, NE, Quad Cities, IA/IL, La Crosse, WI, Milwaukee, WI, Chicago, IL, central Illinois, IL, northern Indiana, IN, Indianapolis, IN, northern Indiana, IN, and Grand Rapids, MI. Thanks to Scott Lincoln, WFO Chicago for working with numerous offices to gather and refine this regional map.

Iowa Environmental Mesonet (IEM) feature showing August 11, 2020 Aqua MODIS satellite image showing crop damage (smiliar to above) with wind reports overlaid. Full feature can be viewed here. Image courtesy of the Iowa Environmental Mesonet.

NASA Aqua satellite MODIS imagery toggle between July 28, 2020 and August 15, 2020 showing the approximate damage area to cropland (outlined) from the derecho that moved across Iowa on August 10, 2020. Imagery courtesy MODIS Today at University of Wisconsin-Madison Space Science and Engineering Center.

NASA TERRA satellite MODIS imagery toggle between July 28, 2020 and August 11, 2020 showing the approximate damage to cropland (outlined) from the derecho that moved across Iowa on August 10, 2020. Imagery courtesy MODIS Today at University of Wisconsin-Madison Space Science and Engineering Center.

NASA/NOAA Suomi Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band showing the nighttime lights in Iowa. The loop starts on the morning of August 10, 2020 before the derecho as a reference of nighttime lights in Iowa. The following images shows the progression from peak power outages on the morning of August 11 to the gradually and ongoing restoration on the mornings of the 12th, 14th, and 16th. Not all nights were cloudless so 'blurring' of lights may occur in some areas. Courtesy NASA Worldview.

USDA major/minor corn areas with NWS storm reports overlaid shows the derecho swept through major corn producing areas of Iowa, Illinois and Indiana on August 10, 2020. Courtesy of the USDA Weekly Weather and Crop Bulletin - August 18, 2020.

Toggle between August 2, 16, and 23, 2020 showing a drop in the USDA Good to Excellent Corn Condition in Iowa. This drop in Iowa is a result of both the ongoing drought and the derecho. Data are from USDA-NASS Maps and are shared by Brad Rippey from USDA-Office of the Chief Economist World Agricultural Outlook Board.

Toggle between August 2, 16, and 23, 2020 showing a drop in the USDA Good to Excellent Soybean Condition in Iowa. This drop in Iowa is a result of both the ongoing drought and the derecho. Data are from USDA-NASS Maps and are shared by Brad Rippey from USDA-Office of the Chief Economist World Agricultural Outlook Board.

Hourly radar images of the derecho's progression across the region. Image courtesy NWS Chicago (original).

Derecho's path across the region on August 10, 2020 was over 750 miles! Image courtesy NWS Storm Prediction Center (original).

#Drecho Storm Summary.
Max customers out at one time: 1.4 million
Total customers Affected: Over 1.9 Million
759k in #Illinois
585k in #Iowa
283k in #Indiana
345k in other states
Source: https://t.co/8cAFt3zGJe pic.twitter.com/KUv6ZaZ7TD
— PowerOutage.us (@PowerOutage_us) August 13, 2020

Power outages caused as the derecho moved through Iowa into Indiana on August 10, 2020. Courtesy PowerOutage.us

Iowa Geological Survey's (IGS) real-time seismometer near Des Moines, IA captured the derecho as it moved through the metro. The IGS' Jason Vogelgesang says, "You can see the waveform responding to the immense wind, beginning at 10:26am & fading back to normal background conditions at 12:08pm". Each line represents 30 minutes of time from left to right and goes from 7am at the top of the image to 7pm at the bottom of the image. Original post on IGS Facebook page (note annotated time on their Facebook graphic corrected in the comments). Image courtesy Iowa Geological Survey.

Photos

Photos from around central Iowa show the damage and devastation from the August 10, 2020 derecho
Additional photos/videos on this Twitter Moment

Defoliated soybeans south of Jefferson, IA
(Courtesy Craig Cogil)

Flattened corn near Scranton, Iowa
(Courtesy Mike Zevenbergen @MikeZevenbergen)

Broken tree limbs, Merle Hay neighborhood, Des Moines
(courtesy NWS Des Moines)

Broken tree hanging across road, Merle Hay neighborhood, Des Moines
(courtesy NWS Des Moines)


Broken window, eastern Greene County, Iowa (Courtesy Megan Holz, @meganlholz)	Tree into house and through sliding glass door, eastern Greene County, Iowa (Courtesy Megan Holz, @meganlholz)	Toppled power lines, eastern Greene County, Iowa (Courtesy Megan Holz, @meganlholz)	Damaged grain bins, eastern Greene County, Iowa (Courtesy Megan Holz, @meganlholz)


Aerial view of the flattened corn in Tama County. (Courtesy of Kip Ladage)	Grain bins crushed in Tama County. (Courtesy of Kip Ladage)	Flattened corn in Tama County. (Courtesy of Kip Ladage)	Hog confinement building demolished in Tama County. (Courtesy of Kip Ladage)

Roland, Iowa. (Courtesy of Angela Ruden)

Elk Horn, Iowa. (Courtesy of Brandon Baggett)

Bondurant, Iowa. (Courtesy of Brennan Jontz)


Randall, Iowa (Courtesy Hamilton County Emergency Management)	Randall, Iowa. (Courtesy of Hamilton County Emergency Management)	Farm House Museum. Iowa State University. (Courtesy of Allison Sheridan)	Marshalltown, Iowa. (Courtesy of Lindsay Cramer)

Rockwell City, Iowa. (Courtesy of Randy VanEvery)

Perry, Iowa. (Courtesy of Rachel Lange)

Huxley, Iowa. (Courtesy of Chrystal Brillhart)

Damaged grain bin in Dallas County. (Courtesy of Dallas County Emergency Manager AJ Seely)

Big tree on a house in Tama County (Courtesy of Darrell Ross)

West side of Ames, Iowa. (Courtesy NWS Des Moines)

Ames, Iowa. (Courtesy of City of Ames)

Ames, Iowa. (Courtesy Jason Mikkelsen)


Tree snapped at base in Manning, Iowa. (Courtesy of Amy Haskins)	Tree snapped in Manning. (Courtesy Amy Haskins)	Tree snapped at base in Manning, Iowa. (Courtesy of Amy Haskins)	Broken tree branch in Manning, Iowa. (Courtesy of Amy Haskins)


Flattened corn at sunset near Adel, Iowa. (Courtesy of Lisa Schmitz)	Flattened corn near Bouton, Iowa. (Courtesy Lisa Schmitz)	Building damaged in Woodward, Iowa (Courtesy of AJ Seely, Dallas County Emergency Management)	Tipped over livestock semi at a gas station on Highway 141 and 169.(Courtesy of AJ Seely, Dallas County Emergency Managment)

Videos

Videos that captured the intense winds and destruction from around central Iowa.

Video from Huxley, Iowa. Courtesy of Jeff Wood.

Video from Dysart, Iowa. Courtesy of Chad Spore.

Video from Ankeny, Iowa. Courtesy of Jared Flater.

Video from Huxley, Iowa. Courtesy of Nick Glenn.

Video from Boone, Iowa. Courtesy of Jake Randolph.

Video from Kiron, Iowa. Courtesy of Kelli Fineran.

Radar & Satellite

Multi-Radar Multi-Sensor animation of the derecho's path through Iowa from 4am to 4pm on August 10, 2020.

GOES-East Sandwich (blend of visible and infrared) loop (Courtesy William Churchill, NWS)

Radar loop from the Iowa Environmental Mesonet of the derecho's progression across Iowa from 8am to 2pm on August 10, 2020. Courtesy of the Iowa Environmental Mesonet.

Satellite Blog DiscUssions

Research Article(s)

Satellite-Based Characterization of Convection and Impacts from the Catastrophic 10 August 2020 Midwest U.S. Derecho (Bulletin of the American Meteorological Society)

Storm Reports

August 10, 2020 IEM Local Storm Reports Map

SPC Storm Reports from August 10, 2020

Interactive Map - Storm Prediction Center

Iowa Environmental Mesonet Local Storm Reports Map

August 10, 2020 IEM Local Storm Reports Map

One minute wind observations at the Des Moines International Airport (KDSM) on August 10, 2020 in the late morning showing a wind gust of 75 mph with wind gusts over 50 mph for over 20 minutes. Image courtesy of the Iowa Environmental Mesonet. Full feature can be viewed here.

Iowa Atmospheric Observatory Tall Tower, located near Zearing, Iowa, shows a maximum, instantaneous 10 meter wind speed max of 46.71 m/s, which is 104 mph, at 11:26.38. Not shown, but at 80m, which is the typical hub height of a wind turbine, the maximum, instantaneous wind speed was 53.88 m/s, which is 120 mph, at 11:26.37. Wind gusts for storm reports are 5 second averages versus instantaneous gusts. Image courtesy of the Iowa Environmental Mesonet. You can view the data here.

Iowa Environmental Mesonet - Derecho Peak Wind Gusts (variety of automated weather stations) and a listing of local storm reports from across Iowa.

Text Summary of Storm Reports - Issued August 10, 2020 at 316pm CDT

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
316 PM CDT MON AUG 10 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0930 AM     TSTM WND DMG     DENISON                 42.02N 95.35W
08/10/2020                   CRAWFORD           IA   LAW ENFORCEMENT  

            LAW REPORTS TREE DAMAGE IN TOWN - TREE FELL 
            ON NEIGHBORS CAR. TREE DAMAGE THROUGHOUT THE 
            COUNTY. TIME ESTIMATED. 

0930 AM     TSTM WND DMG     KIRON                   42.19N 95.33W
08/10/2020                   CRAWFORD           IA   LAW ENFORCEMENT  

            SEMI JACKKNIFED DUE TO STRONG WINDS. 

0936 AM     TSTM WND DMG     MANNING                 41.91N 95.06W
08/10/2020                   CARROLL            IA   TRAINED SPOTTER  

            LARGE TREE LIMB ROUGHLY 6 INCHES IN DIAMETER 
            AND 20 FEET LONG DOWN. SEVERAL SMALLER TREE 
            LIMBS DOWN AS WELL. 

0945 AM     TSTM WND DMG     BUCK GROVE              41.92N 95.40W
08/10/2020                   CRAWFORD           IA   LAW ENFORCEMENT  

            TREE DAMAGE REPORTED AROUND TOWN. 

1000 AM     TSTM WND DMG     3 WSW BAGLEY            41.83N 94.49W
08/10/2020                   GUTHRIE            IA   EMERGENCY MNGR   

            OUTBUILDING HAD ROOF BLOWN OFF. TIME 
            ESTIMATED. 

1002 AM     TSTM WND GST     3 WSW GLIDDEN           42.05N 94.79W
08/10/2020  M74 MPH          CARROLL            IA   AWOS             



1010 AM     TSTM WND GST     4 SSE ATLANTIC          41.34N 95.00W
08/10/2020  E60 MPH          CASS               IA   PUBLIC           



1014 AM     TSTM WND GST     5 SSE GUTHRIE CENTER    41.61N 94.45W
08/10/2020  M65 MPH          GUTHRIE            IA   MESONET          



1015 AM     TSTM WND DMG     TEMPLETON               41.92N 94.94W
08/10/2020                   CARROLL            IA   TRAINED SPOTTER  

            LARGE TREES DOWN BLOCKING ROADS. WIND STILL 
            BLOWING. 

1021 AM     TSTM WND GST     4 WSW BAGLEY            41.82N 94.49W
08/10/2020  E65 MPH          GUTHRIE            IA   EMERGENCY MNGR   

            ALONG WITH PEA SIZED HAIL AND HEAVY 
            RAINFALL. 

1025 AM     TSTM WND DMG     PERRY                   41.84N 94.10W
08/10/2020                   DALLAS             IA   EMERGENCY MNGR   

            TWO FOOT DIAMETER TREE LIMB DOWN IN PERRY. 

1026 AM     TSTM WND GST     1 N PERRY               41.86N 94.10W
08/10/2020  E70 MPH          DALLAS             IA   PUBLIC           

            BRANCHES DOWN, POWER OUT. 

1030 AM     TSTM WND DMG     1 ESE MARSHALLTOWN      42.03N 92.89W
08/10/2020                   MARSHALL           IA   EMERGENCY MNGR   

            ROOF DAMAGE TO A HOME. TIME ESTIMATED. 

1030 AM     TSTM WND GST     CHURDAN                 42.16N 94.48W
08/10/2020  E70 MPH          GREENE             IA   TRAINED SPOTTER  

            DEBRIS ON ROADS AS WELL. 

1032 AM     TSTM WND DMG     7 NW ADEL               41.68N 94.12W
08/10/2020                   DALLAS             IA   TRAINED SPOTTER  

            LARGE TREE LIMB DOWN HIT HOUSE. WITHOUT 
            POWER NOW. ESTIMATE 60 MPH WINDS OR HIGHER. 

1033 AM     TSTM WND GST     2 WSW MINBURN           41.75N 94.06W
08/10/2020  E70 MPH          DALLAS             IA   FIRE DEPT/RESCUE 

            60 TO 70 MPH WIND GUSTS. 

1034 AM     TSTM WND DMG     GUTHRIE CENTER          41.68N 94.50W
08/10/2020                   GUTHRIE            IA   TRAINED SPOTTER  

            TREES DOWN. WIND STILL BLOWING. 

1034 AM     TSTM WND DMG     ROCKWELL CITY           42.40N 94.63W
08/10/2020                   CALHOUN            IA   TRAINED SPOTTER  

            8 INCH TREE LIMBS DOWN. POWER LINES DOWN. 
            TREES DOWN ALL OVER TOWN. 

1037 AM     TSTM WND GST     2 SE ADEL               41.59N 94.00W
08/10/2020  E65 MPH          DALLAS             IA   PUBLIC           

            POWER OFF/ON. WINDS HIGHER THAN 60 MPH. 

1038 AM     TSTM WND GST     2 WSW PILOT MOUND       42.15N 94.05W
08/10/2020  E65 MPH          BOONE              IA   TRAINED SPOTTER  

            TREE DAMAGE REPORTED. WINDS GREATER THAN 60 
            MPH ESTIMATED. 

1040 AM     TSTM WND GST     4 WNW DE SOTO           41.55N 94.08W
08/10/2020  E70 MPH          DALLAS             IA   TRAINED SPOTTER  

            LOTS OF SMALL TREES DOWN AND SEVERAL 
            ANCHORED SWING SETS TOPPLED OVER. 

1047 AM     TSTM WND GST     1 WSW WEST DES MOINES   41.56N 93.78W
08/10/2020  E70 MPH          POLK               IA   TRAINED SPOTTER  

            MILLS CIVIC AND I35; 70 MPH WINDS. SIGN AND 
            TREE DAMAGE. WINDS OF 55 TO 70 LASTED NEARLY 
            20 MINUTES DURING THE SURGE. 

1048 AM     TSTM WND GST     ADEL                    41.62N 94.03W
08/10/2020  M70 MPH          DALLAS             IA   TRAINED SPOTTER  

            WIND REPORTED IN CITY OF ADEL. LIMBS DOWN, 
            OBJECTS BLOWN AROUND. 

1052 AM     TSTM WND DMG     3 ESE BOONE             42.03N 93.82W
08/10/2020                   BOONE              IA   PUBLIC           

            SEMI BLOWN OVER AT US30/HIGHWAY 17 
            INTERCHANGE. TIME ESTIMATED BY RADAR. 

1054 AM     TSTM WND DMG     2 W MURRAY              41.04N 93.98W
08/10/2020                   CLARKE             IA   TRAINED SPOTTER  

            DAMAGE TO HOME FOUNDATION AND SEVERAL LARGE 
            TREE LIMBS DOWN AS WELL AS VERY LARGE TREE 
            TRUNK. 

1054 AM     TSTM WND DMG     LUTHER                  41.97N 93.82W
08/10/2020                   BOONE              IA   TRAINED SPOTTER  

            SEVERAL LARGE TREE LIMBS DOWN, POWER OUT. 

1055 AM     TSTM WND GST     5 WSW CUMMING           41.45N 93.84W
08/10/2020  E75 MPH          MADISON            IA   TRAINED SPOTTER  



1055 AM     TSTM WND DMG     5 NW LOHRVILLE          42.31N 94.63W
08/10/2020                   CALHOUN            IA   TRAINED SPOTTER  

            TREES DOWN, ROOF OFF BUILDING. LOTS OF TREE 
            DAMAGE. 

1056 AM     TSTM WND DMG     CUMMING                 41.48N 93.76W
08/10/2020                   WARREN             IA   PUBLIC           

            POWER OUT NEAR CUMMING, IOWA. 

1057 AM     TSTM WND DMG     BOONE                   42.05N 93.88W
08/10/2020                   BOONE              IA   PUBLIC           

            POWER OUT, TREES DOWN. 

1059 AM     TSTM WND DMG     1 N WINDSOR HEIGHTS     41.63N 93.71W
08/10/2020                   POLK               IA   PUBLIC           

            REPORTED AT 75TH AND DIAMOND, URBANDALE IOWA 
            TREE DAMAGE. 

1100 AM     TSTM WND DMG     1 N BONDURANT           41.70N 93.46W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            NUMEROUS TREES AND POWERLINES DOWN. TIME 
            ESTIMATED. 

1100 AM     TSTM WND GST     1 W URBANDALE           41.64N 93.77W
08/10/2020  M85 MPH          POLK               IA   TRAINED SPOTTER  

            REPORTED AT 112TH NE AND 104TH, DES MOINES 
            FROM PERSONAL WEATHER STATION. TIME 
            ESTIMATED. 

1100 AM     TSTM WND GST     1 N DES MOINES INT AIRP 41.55N 93.66W
08/10/2020  E80 MPH          POLK               IA   TRAINED SPOTTER  

            SEVERAL LARGE TREE LIMBS DOWN AND A COUPLE 
            TREE TRUNKS SNAPPED. ROADS BLOCKED. 

1100 AM     TSTM WND DMG     1 ESE MARSHALLTOWN      42.03N 92.89W
08/10/2020                   MARSHALL           IA   PUBLIC           

            100 TO 120 CARS HAD THEIR WINDOWS BLOWN OUT 
            AT A FACTORY. TIME ESTIMATED. 

1101 AM     TSTM WND GST     3 NE ANKENY             41.76N 93.57W
08/10/2020  M69 MPH          POLK               IA   MESONET          

            MESONET STATION RAKI4 ANKENY - I35 AND NE 
            36TH. 

1102 AM     TSTM WND DMG     FORT DODGE              42.51N 94.18W
08/10/2020                   WEBSTER            IA   EMERGENCY MNGR   

            NUMEROUS TREES DOWN ALONG WITH POWER 
            OUTAGES. 

1103 AM     TSTM WND DMG     CUMMING                 41.48N 93.76W
08/10/2020                   WARREN             IA   TRAINED SPOTTER  

            SEVERAL LARGE TREES DOWN THROUGHOUT THE TOWN 
            OF CUMMING. TIME ESTIMATED BY RADAR. 

1103 AM     TSTM WND GST     INDIANOLA               41.36N 93.56W
08/10/2020  M58 MPH          WARREN             IA   PUBLIC           



1104 AM     TSTM WND GST     DES MOINES INT AIRPORT  41.53N 93.67W
08/10/2020  M75 MPH          POLK               IA   ASOS             

            ASOS STATION KDSM DES MOINES INTERNATIONAL 
            AIRPORT. 

1105 AM     TSTM WND DMG     1 NNW WINDSOR HEIGHTS   41.62N 93.72W
08/10/2020                   POLK               IA   PUBLIC           

            ROOF DAMAGE TO BUCCANEER ARENA. 72ND AND 
            HICKMAN RD. REPORT VIA SOCIAL MEDIA. TIME 
            ESTIMATED. 

1105 AM     TSTM WND DMG     3 S SAYLORVILLE         41.64N 93.63W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            TWELVE INCH TO EIGHT INCH DIAMETER TREES 
            DOWN. 

1106 AM     TSTM WND GST     1 E CLIVE               41.61N 93.75W
08/10/2020  E70 MPH          POLK               IA   NWS EMPLOYEE     

            LOTS OF SMALL BRANCHES DOWN. 

1106 AM     TSTM WND GST     MADRID                  41.87N 93.81W
08/10/2020  M59 MPH          BOONE              IA   MESONET          

            MESONET STATION CW2001 MADRID. 

1107 AM     TSTM WND GST     GILBERT                 42.11N 93.65W
08/10/2020  E70 MPH          STORY              IA   TRAINED SPOTTER  



1110 AM     TSTM WND GST     3 ENE AMES              42.03N 93.57W
08/10/2020  M62 MPH          STORY              IA   MESONET          

            MESONET STATION RAMI4 2 E AMES. 

1110 AM     TSTM WND DMG     1 W JOHNSTON            41.68N 93.75W
08/10/2020                   POLK               IA   NWS EMPLOYEE     

            NW JOHNSTON TREE UPROOTED. TIME ESTIMATED. 

1110 AM     TSTM WND GST     1 W ELKHART             41.79N 93.53W
08/10/2020  M85 MPH          POLK               IA   MESONET          

            MESONET STATION UP752 0.6 W ELKHART (UPR). 

1110 AM     TSTM WND DMG     ALTOONA                 41.65N 93.48W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            BRANCHES DOWN. 

1110 AM     TSTM WND DMG     2 WNW ANKENY            41.74N 93.64W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            6 IN LARGER TREE LIMBS DOWN. POWER OUTAGES. 
            TIME ESTIMATED BY RADAR. WIND GUSTS OF 50 
            MPH LASTED 30 MINUTES. REPORT 11:40 AM. 

1111 AM     TSTM WND GST     1 N AMES                42.04N 93.63W
08/10/2020  E70 MPH          STORY              IA   TRAINED SPOTTER  

            ESTIMATED OVER 70 MPH WINDS IN AMES. 

1112 AM     TSTM WND DMG     URBANDALE               41.64N 93.74W
08/10/2020                   POLK               IA   BROADCAST MEDIA  

            TREES DOWN. DAMAGE TO ROOFS. RELAYED BY 
            WOI-TV. 

1113 AM     TSTM WND DMG     1 NNW WINDSOR HEIGHTS   41.62N 93.72W
08/10/2020                   POLK               IA   BROADCAST MEDIA  

            PART OF THE DES MOINES BUCCANEERS ROOF BLOWN 
            OFF. RELAYED BY WHO-TV. 

1114 AM     TSTM WND DMG     2 NW DES MOINES         41.60N 93.64W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            LARGE TREE BRANCHES DOWN. 

1115 AM     TSTM WND DMG     ZEARING                 42.16N 93.30W
08/10/2020                   STORY              IA   TRAINED SPOTTER  

            TREE AND BIN DAMAGE. TIME ESTIMATED. 

1115 AM     TSTM WND GST     3 E SAYLORVILLE         41.68N 93.57W
08/10/2020  M78 MPH          POLK               IA   AWOS             

            AWOS STATION KIKV ANKENY AIRPORT. 

1116 AM     TSTM WND DMG     CARLISLE                41.50N 93.49W
08/10/2020                   WARREN             IA   PUBLIC           

            LOTS OF TREE DAMAGE IN CARLISLE. SOCIAL 
            MEDIA. 

1116 AM     TSTM WND DMG     2 NW CLIVE              41.63N 93.79W
08/10/2020                   POLK               IA   PUBLIC           

            128TH AND DOUGLAS URBANDALE, IOWA FENCE 
            BLOWN DOWN WITH HIGH WINDS. 

1119 AM     TSTM WND DMG     3 ESE WEST DES MOINES   41.56N 93.70W
08/10/2020                   POLK               IA   TRAINED SPOTTER  

            LARGE TREE DOWN. 

1120 AM     TSTM WND DMG     NEVADA                  42.02N 93.45W
08/10/2020                   STORY              IA   PUBLIC           

            TREES DOWN WITH HIGH WINDS. POWER ON/OFF. 

1120 AM     TSTM WND GST     COLFAX                  41.68N 93.24W
08/10/2020  E80 MPH          JASPER             IA   PUBLIC           

            WINDS OF 70 TO 80 MPH. 

1124 AM     TSTM WND GST     1 WSW AMES              42.02N 93.64W
08/10/2020  E70 MPH          STORY              IA   TRAINED SPOTTER  

            IOWA STATE CAMPUS. 65 TO 75 MPH WINDS 
            ESTIMATED. EXTENSIVE TREE DAMAGE THROUGHOUT 
            AMES. NO POWER. 

1124 AM     TSTM WND DMG     COLFAX                  41.68N 93.23W
08/10/2020                   JASPER             IA   TRAINED SPOTTER  

            LARGE TREE BLOCKING BOTH LANES OF STATE 
            HIGHWAY F48 IN TOWN OF COLFAX. 

1126 AM     TSTM WND DMG     2 W ANKENY              41.74N 93.64W
08/10/2020                   POLK               IA   PUBLIC           

            MAILBOXES BLOWN DOWN, ALONG WITH TREES AND 
            BRANCHES OF UNDETERMINED SIZE. 

1126 AM     TSTM WND GST     2 ENE LAMONI            40.63N 93.90W
08/10/2020  M62 MPH          DECATUR            IA   ASOS             

            ASOS STATION KLWD LAMONI AIRPORT. 

1129 AM     TSTM WND DMG     NEWTON                  41.70N 93.05W
08/10/2020                   JASPER             IA   TRAINED SPOTTER  

            DAMAGE REPORTED THROUGHOUT TOWN. TREE DAMAGE 
            WITH ROADS BLOCKED. DELAYED REPORT AT 12:30 
            PM. RADAR ESTIMATED 11:29 AM. 

1130 AM     TSTM WND GST     2 E SAYLORVILLE         41.69N 93.59W
08/10/2020  M77 MPH          POLK               IA   PUBLIC           

            PEAK WIND GUST OF 77 MPH VIA DAVIS WEATHER 
            STATION. TREE BRANCHES OF 2-3 INCH DIAMETER 
            BROKEN AND ON THE GROUND. 4 INCH TREE BROKE 
            OFF AT THE GROUND. 

1134 AM     TSTM WND DMG     SLATER                  41.88N 93.68W
08/10/2020                   STORY              IA   TRAINED SPOTTER  

            LARGE TREE BRANCHES DOWN. STREET SIGNS BLOWN 
            DOWN IN TOWN. PART OF HOUSE ROOF BLOWN OFF. 
            EXACT TIME UNKNOWN. 

1135 AM     TSTM WND GST     3 SSW KNOXVILLE         41.28N 93.12W
08/10/2020  M71 MPH          MARION             IA   AWOS             

            AWOS STATION KOXV KNOXVILLE AIRPORT. 

1138 AM     TSTM WND GST     3 S HUBBARD             42.27N 93.30W
08/10/2020  M77 MPH          HARDIN             IA   MESONET          

            MESONET STATION FW1669 HUBBARD. 

1139 AM     TSTM WND DMG     GRIMES                  41.69N 93.79W
08/10/2020                   POLK               IA   AMATEUR RADIO    

            MULTIPLE LARGE TREE LIMBS DOWN, LARGEST IS 
            EIGHT INCHES IN DIAMETER. EXACT TIME 
            UNKNOWN. 

1140 AM     TSTM WND GST     2 SSW PRAIRIE CITY      41.57N 93.26W
08/10/2020  M85 MPH          JASPER             IA   MESONET          

            MESONET STATION NSWI4 NEIL SMITH NWR RAWS. 

1143 AM     TSTM WND GST     3 SW MARSHALLTOWN       42.00N 92.96W
08/10/2020  M91 MPH          MARSHALL           IA   MESONET          

            MESONET STATION RMTI4 MARSHALLTOWN (US 30) - 
            IA DOT RWIS. 

1143 AM     TSTM WND GST     HUBBARD                 42.31N 93.31W
08/10/2020  E70 MPH          HARDIN             IA   EMERGENCY MNGR   

            NUMEROUS LARGE TREES DOWN. WINDS ESTIMATED 
            AT 70 MPH. 

1147 AM     TSTM WND DMG     2 WSW UNION             42.24N 93.09W
08/10/2020                   HARDIN             IA   TRAINED SPOTTER  

            DAMAGE TO BARNS AND ROOFS. 

1150 AM     TSTM WND GST     4 E ALBION              42.12N 92.92W
08/10/2020  M99 MPH          MARSHALL           IA   ASOS             

            ASOS STATION KMIW MARSHALLTOWN AIRPORT. PEAK 
            GUST THUS FAR. 

1151 AM     TSTM WND GST     2 S MARSHALLTOWN        42.01N 92.91W
08/10/2020  E95 MPH          MARSHALL           IA   STORM CHASER     

            ESTIMATED WINDS OF 90 TO 100 MPH. 

1151 AM     TSTM WND DMG     2 S MARSHALLTOWN        42.01N 92.91W
08/10/2020                   MARSHALL           IA   STORM CHASER     

            SEVERAL LARGE SECTIONS OF ROOFS BLOWN OFF 
            BUILDINGS ALONG OLD HIGHWAY 30 ON SOUTH PART 
            OF MARSHALLTOWN. 

1152 AM     TSTM WND GST     2 WNW LE GRAND          42.02N 92.81W
08/10/2020  M106 MPH         MARSHALL           IA   MESONET          

            PERSONAL WEATHER STATION KIAMARSH15. 

1155 AM     TSTM WND GST     TOLEDO                  42.00N 92.58W
08/10/2020  E70 MPH          TAMA               IA   EMERGENCY MNGR   

            70 MPH PLUS WIND GUST IN TOLEDO. TREE STRUCK 
            OFFICE. 

1157 AM     TSTM WND GST     LEIGHTON                41.34N 92.78W
08/10/2020  M75 MPH          MAHASKA            IA   MESONET          

            REPORTED AT LEIGHTON, IA. PWS. 

1158 AM     TSTM WND DMG     STATE CENTER            42.02N 93.17W
08/10/2020                   MARSHALL           IA   EMERGENCY MNGR   

            SIGNIFICANT DAMAGE IN STATE CENTER. NUMEROUS 
            CARS BLOWN OFF US30 AND FLIPPED. 

1158 AM     TSTM WND GST     2 SW CONRAD             42.21N 92.90W
08/10/2020  E75 MPH          MARSHALL           IA   TRAINED SPOTTER  



1200 PM     TSTM WND GST     3 S CHELSEA             41.88N 92.39W
08/10/2020  E90 MPH          TAMA               IA   TRAINED SPOTTER  



1200 PM     TSTM WND DMG     1 S MARSHALLTOWN        42.02N 92.91W
08/10/2020                   MARSHALL           IA   PUBLIC           

            SIGNIFICANT TREE AND STRUCTURAL DAMAGE. 
            EXACT TIME UNKNOWN. 

1201 PM     TSTM WND DMG     3 N TOLEDO              42.04N 92.58W
08/10/2020                   TAMA               IA   CO-OP OBSERVER   

            60X90 FOOT MACHINE SHED COMPLETELY 
            DEMOLISHED. NEIGHBORS (EMPTY) GRAIN BINS 
            WERE BLOWN ACROSS HIGHWAY 63. SEVERAL LARGE 
            TREES SNAPPED AND/OR UPROOTED. MEASURED WIND 
            GUST OF 78 MPH BEFORE WEATHER STATION GAVE 
            OUT. 

1210 PM     TSTM WND DMG     3 SSW GRINNELL          41.70N 92.74W
08/10/2020                   POWESHIEK          IA   TRAINED SPOTTER  

            SEMI BLOWN OVER ON I-80 JUST WEST OF THE 
            GRINNELL INTERCHANGE. 

1215 PM     TSTM WND DMG     REINBECK                42.33N 92.60W
08/10/2020                   GRUNDY             IA   TRAINED SPOTTER  

            TREES DOWN ALL OVER TOWN ON THE ROADS. 
            ESTIMATED WIND SPEEDS 70 MPH. TIME 
            ESTIMATED. 

1219 PM     TSTM WND GST     1 S GRUNDY CENTER       42.34N 92.77W
08/10/2020  E60 MPH          GRUNDY             IA   TRAINED SPOTTER  

            ALONG WITH PEA SIZED HAIL. 

1235 PM     TSTM WND GST     OTTUMWA                 41.02N 92.42W
08/10/2020  E60 MPH          WAPELLO            IA   TRAINED SPOTTER

Tornadoes

Tornado #1 - SW of La Moille
Marshall County

Date	8/10/2020
Time (Local)	11:30am - 11:31am CDT
EF Rating	EF-U
Est. Peak Winds	Unknown
Path Length	1.03 miles
Max Width	50 yards
Injuries/Deaths	0 Injury / 0 Deaths
Summary: Brief QLCS tornado on leading edge of convection. Path found via high resolution satellite imagery. The tornado impacted no damage indicators, hence the EFU rating.

Track Map

Downloadable KMZ File

Tornado #2 - NE of Minerva
Marshall County

Date	8/10/2020
Time (Local)	11:36am - 11:37am CDT
EF Rating	EF-U
Est. Peak Winds	Unknown
Path Length	0.42 miles
Max Width	50 yards
Injuries/Deaths	0 Injury / 0 Deaths
Summary: Brief tornado captured from post event UAS survey. Stayed in cropland with no impacts to damage indicators, hence the EFU rating.

Track Map

Downloadable KMZ File

Tornado #3 - Northwest of Marshalltown
Marshall County

Date	8/10/2020
Time (Local)	11:39am - 11:42am CDT
EF Rating	EF-1
Est. Peak Winds	100 mph
Path Length	2.88 miles
Max Width	100 yards
Injuries/Deaths	0 Injury / 0 Deaths
Summary: Tornado initially found from high resolution satellite imagery and confirmed via UAS overflight. Damage was done to crop and trees. Some minor damage to housing structures as well, but mostly superficial.

Track Map

Downloadable KMZ File

Tornado #4 - SE of Gladbrook
Tama County

Date	8/10/2020
Time (Local)	12:01pm - 12:03pm CDT
EF Rating	EF-U
Est. Peak Winds	Unknown
Path Length	1.48 miles
Max Width	40 yards
Injuries/Deaths	0 Injury / 0 Deaths
Summary: Tornado associated with QLCS derecho first observed via high resolution satellite imagery. Path was also overflown by UAS confirming convegent path of debris. No damage indicators were impacted, hence the EFU designation.

Track Map

Downloadable KMZ File

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

Environment

SPC Event Review Webpage for August 10, 2020


NWS Quad Cities' Observed Sounding at 1200 UTC (7 a.m. CT) the morning of the derecho.	Special sounding launched at 1700 UTC (Noon CT) ahead of the derecho in eastern Iowa.	Regional radar loop


850mb height (m, black), temp (C, red), dewpoint (C, green), and wind (knots)	700mb height (m), wind (knots), temp (C, red), and 700-500mb mean RH>=70.	Surface analysis and satellite animation showing the progression of the derecho through the region.


Downdraft convective available potential energy (DCAPE) can provide an estimate of potential downdrafts of rain cooled air to the surface. Larger DCAPE values are typically associated with stronger downdrafts and possibly stronger wind gusts.	Derecho composite parameter attempts to identify areas that may become cold pool dominant for wind events.	Most unstable convective available potential energy (MUCAPE) showed extreme instability of 6000 J/kg and theta-e difference of 30C or greater. Theta-e differences greater than 30C are shown and even 35C later in the event indicate potential strength of the cold pool.


3-hour Surface Based CAPE change clearly shows the amount of energy the derecho used as it moved eastward across Iowa into Illinois.	Deep layer moisture convergence at 16 UTC (11 a.m CT).	Energy-Helicity Index (EHI) at 1600 UT (11 a.m. CT).

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.

1980 Derecho

1983 Derecho

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

Derechos Facts & FAQs

Derecho Facts

A derecho (pronounced duh-REY-cho) produces a swath of particularly damaging thunderstorm winds (specifically, wind gusts of at least 58 mph along most of its length with several well-separated 75 mph or greater gusts) over an area at least 250 miles long.
Wind speeds in a derecho can exceed 100 mph, which is equivalent to that of an EF-1 tornado, but over a vastly larger area than a tornado would impact.
Tornadoes can also be embedded within derechos and produce concentrated areas of even more intense damage.
Derechos develop in an environment with very warm and moist air at the surface, colder air aloft, and moderate to strong winds at upper levels of the atmosphere.
The term was originated by Dr. Gustavus Hinrichs of the University of Iowa, first appearing in the American Meteorological Journal in 1888; he coined the term to distinguish straight-line winds from the damage caused by tornadoes (the word "derecho" comes from the Spanish term meaning "direct" or "straight ahead").

Derecho FAQs

The August 10, 2020 derecho has been both equally impressive and devastating in its effect across Iowa and surrounding states. The event has often been compared to an inland hurricane or hurricanes in general. While this does help people relate to the type of wind damage seen in this event, this is where the comparisons between derechos and hurricanes end.

Here are a few of the key distinctions between derechos and hurricanes.

â€‹A derecho lifespan typically lasts from several hours up to a day and a half, but usually no longer. Hurricanes can maintain themselves for days or even weeks as long as they can remain over warm ocean waters.
The damaging winds from a derecho typically last less than a half an hour at a given location whereas a hurricane's wind speeds can last hours at a given location.
Derechos have a forward motion that tends to be quite rapid and is usually 50 mph or higher. Hurricanes on the other hand typically move around 15 to 20 mph or less.
Derechos can occur over land and/or water and maintain their intensity. However, once a hurricane leaves the warm ocean waters, which is the energy that feeds these systems, and move over land they quickly weaken.

Finally, while the damage from a derecho can look like tornado damage, a key distinction between a derecho and a tornado is the widespread damage swath. A tornado's width is generally less than a mile with the widest tornado width around 2.5 miles. A derecho on the other hand produces damage over a much larger width of many miles.

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Heat and Fire Weather Concerns in the West

August 10, 2020 Derecho

Videos that captured the intense winds and destruction from around central Iowa.