Alert archive / Iowa / Tornado Warnings in 2026
Tornado Warning 11, NWS Des Moines, IA
NWS Des Moines, IA issued this tornado warning at Apr 17, 2026, 2:38 PM CDT for Black Hawk County, Bremer County, Butler County, Iowa. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Apr 17, 2026, 2:38 PM CDT (19:38 UTC)
- Expired
- Apr 17, 2026, 3:08 PM CDT
- In force
- 30 min
- Issued by
- NWS Des Moines, IA
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 1.5 in
Counties Black Hawk County, IA, Bremer County, IA, Butler County, IA
The radar
The Des Moines radar (KDMX), 151 km from the middle of the area, began a volume at 19:39 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.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this tornado warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Apr 17, 12:40 PM CDT | Tornado Watch | SPC | 9 hr |
The nearest sounding before it
Minneapolis, MN (KMPX), launched 12:00Z, 7.6 hours before the alert went out and 258 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2301 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 188 m²/s²
- 0-3 km storm-relative helicity
- 229 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
241
WFUS53 KDMX 171938
TORDMX
IAC013-017-023-172030-
/O.NEW.KDMX.TO.W.0011.260417T1938Z-260417T2030Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Des Moines IA
238 PM CDT Fri Apr 17 2026
The National Weather Service in Des Moines has issued a
* Tornado Warning for...
Northwestern Black Hawk County in northeastern Iowa...
Central Bremer County in northeastern Iowa...
Southeastern Butler County in north central Iowa...
* Until 330 PM CDT.
* At 238 PM CDT, a severe thunderstorm capable of producing a tornado
was located 5 miles northwest of New Hartford, or 10 miles
southeast of Allison, moving northeast at 35 mph.
HAZARD...Tornado and ping pong ball size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* This dangerous storm will be near...
Shell Rock around 245 PM CDT.
Waverly and Waverly Municipal Airport around 250 PM CDT.
Tripoli around 315 PM CDT.
Frederika around 320 PM CDT.
Other locations impacted by this tornadic thunderstorm include
Janesville, Frederika, Waverly Municipal Airport, and Readlyn.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4268 9214 4256 9277 4263 9279 4291 9227
TIME...MOT...LOC 1938Z 235DEG 31KT 4263 9269
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
$$
Donavon2 follow-up statements
719
WWUS53 KDMX 171948
SVSDMX
Severe Weather Statement
National Weather Service Des Moines IA
248 PM CDT Fri Apr 17 2026
IAC013-017-023-172030-
/O.CON.KDMX.TO.W.0011.000000T0000Z-260417T2030Z/
Black Hawk IA-Bremer IA-Butler IA-
248 PM CDT Fri Apr 17 2026
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 330 PM CDT FOR
NORTHWESTERN BLACK HAWK...BREMER AND SOUTHEASTERN BUTLER COUNTIES...
At 247 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Janesville, or 5 miles southwest of Waverly, moving
northeast at 40 mph.
HAZARD...Tornado and quarter size hail.
SOURCE...Radar indicated rotation. A funnel cloud was reported near
Parkersburg around 237 pm.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This dangerous storm will be near...
Waverly and Janesville around 250 PM CDT.
Denver around 255 PM CDT.
Readlyn around 305 PM CDT.
Tripoli around 310 PM CDT.
Other locations impacted by this tornadic thunderstorm include
Janesville, Frederika, Waverly Municipal Airport, and Readlyn.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4258 9265 4268 9265 4291 9227 4268 9214
TIME...MOT...LOC 1947Z 247DEG 36KT 4266 9254
TORNADO...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
$$
Donavon833 WWUS53 KDMX 172008 RRA SVSDMX Severe Weather Statement National Weather Service Des Moines IA 308 PM CDT Fri Apr 17 2026 IAC013-017-023-172018- /O.CAN.KDMX.TO.W.0011.000000T0000Z-260417T2030Z/ Black Hawk IA-Bremer IA-Butler IA- 308 PM CDT Fri Apr 17 2026 ...THE TORNADO WARNING FOR NORTHWESTERN BLACK HAWK...BREMER AND SOUTHEASTERN BUTLER COUNTIES IS CANCELLED... The storm which prompted the warning has weakened below severe limits, and no longer appears capable of producing a tornado. Therefore, the warning has been cancelled. A Tornado Watch remains in effect until 800 PM CDT for north central and northeastern Iowa. LAT...LON 4258 9265 4268 9265 4291 9227 4268 9214 TIME...MOT...LOC 2006Z 235DEG 31KT 4276 9234 $$ Donavon
What forecasters said that day
The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Des Moines, IA wrote its last area forecast discussion before this tornado warning went out at Apr 17, 1:01 PM CDT, 1 hour 37 minutes earlier. Its key messages:
- Enhanced Risk (level 3 of 5) in eastern Iowa. All severe hazards, including large hail, damaging wind, and tornadoes, are possible with storms today.
- Much cooler this weekend with overnight lows in the 20s and 30s.
- Mild and dry to start the week with thunderstorms returning to the forecast by late week.
Area forecast discussion, Apr 17, 1:01 PM CDT, 1 hour 37 minutes before
Area Forecast Discussion National Weather Service Des Moines IA 101 PM CDT Fri Apr 17 2026 .KEY MESSAGES... - Enhanced Risk (level 3 of 5) in eastern Iowa. All severe hazards, including large hail, damaging wind, and tornadoes, are possible with storms today. - Much cooler this weekend with overnight lows in the 20s and 30s. - Mild and dry to start the week with thunderstorms returning to the forecast by late week. && .SHORT TERM /THROUGH TONIGHT/... Issued at 101 PM CDT Fri Apr 17 2026 The surface low early this afternoon is centered across north central Iowa with attendant sharp cold front pushing across the state. The impact was already being felt this morning in northwest Iowa when Estherville fell from 71 degrees at 10am to 43 degrees by 10:07am. Early convection has bubbled in northern Iowa and into Minnesota associated with lift in the vicinity of the surface low. The cold air sharply undercuts the warm and deeply unstable air in place with the primary trough farther to the west. This will allow for a period of some post-frontal elevated storm development, something already noted with elevated showers in northwest Iowa this morning behind the surface front. Across the state two primary ares of convective development are anticipated into the afternoon, noted in midday satellite imagery. The first is pre-frontal convection developing in an area of convergence noted in surface observations across eastern Iowa and visible in a plume of cumulus. A second line of cumulus trails along the cold front across western Iowa that will push across Iowa through the rest of the afternoon. Much of the prefrontal convection is expected to develop east of the area, perhaps clipping far southeastern parts of the area near Ottumwa. There is plenty of available instability with 3000-4000 J/kg of MUCAPE (3000+ MLCAPE) and steep mid level lapse rates of 8+ C/km. Much of this instability is elevated with very little in the lowest 3 km (<100 J/kg). This will limit low level stretching and some of the tornado potential locally, though it is certainly NOT eliminated. The steep mid-level lapse rates, along with well curved hodographs in the low levels will help with rotating updrafts and hail growth. Storms are expected to quickly grow upscale. As this happens the initial discrete development will become multi-cell to linear as it pushes east, transitioning to a damaging with threat with tornado potential along the line. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 101 PM CDT Fri Apr 17 2026 Much colder air pushes in with the cold front as temperatures fall into the 30s tonight. Saturday remains breezy with continued cold air advection and the enhanced pressure gradient across the area. Temperatures in the upper 40s north to mid 50s south with 20-25 mph wind through the day. By Sunday winds relax with temperatures warming slightly into the 50s to low 60s. The thermal ridge builds next week, bringing 70s back to the area. Much of the week is dry with storm chances returning late in the week. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1236 PM CDT Fri Apr 17 2026 Breezy southerly winds are increasing across the area ahead of a strong cold front moving across the state today with gusts of 25-30 kts. The front will sweep through this afternoon, exiting east after 00z. Early storms have bubbled across northern Iowa this morning and may come near KMCW in the next hour or so, however recent trends indicate this should miss KMCW so have kept from that TAF at this time. The main line of storms will develop in east central Iowa. This may come near KDSM and KALO, however satellite shows initiation should be just east of those sites so have removed mentions from those sites. KOTM will see the bulk of thunderstorm activity this afternoon from around 19-20z through 00s. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && SHORT TERM...Hagenhoff LONG TERM...Hagenhoff AVIATION...Hagenhoff
Hazardous weather outlook, Apr 17, 4:38 AM CDT, 10 hours before
Hazardous Weather Outlook National Weather Service Des Moines IA 438 AM CDT Fri Apr 17 2026 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075- 081>086-092>097-180945- Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo- Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun- Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene- Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper- Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union- Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne- Appanoose-Davis- 438 AM CDT Fri Apr 17 2026 This Hazardous Weather Outlook is for portions of central Iowa. .DAY ONE...Today and tonight There is an Enhanced Risk (Level 3 of 5) for severe thunderstorms across southeast Iowa on Friday. There is a Slight Risk (Level 2 of 5) for severe storms more into central Iowa. Damaging winds and tornadoes are the primary threats. Large hail is also possible, especially early in the event. Additional rises on rivers and streams, with localized minor flooding possible. Ponding and low-end flash flooding is also possible, especially in urban areas. .DAYS TWO THROUGH SEVEN...Saturday through Thursday Freezing temperatures are expected in northern Iowa Friday night and across much of the area Saturday night. Thunderstorm chances return Thursday. .SPOTTER INFORMATION STATEMENT... Spotters will be needed this afternoon.
In the hours before
Local storm report, Apr 17, 2:05 PM CDT, 33 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
205 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0158 PM Hail Ankeny 41.73N 93.60W
04/17/2026 M1.00 Inch Polk IA Public
&&
JR/RDLocal storm report, Apr 17, 2:25 PM CDT, 13 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
225 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0211 PM Hail Des Moines 41.58N 93.62W
04/17/2026 E1.50 Inch Polk IA Public
Multiple reports across the metro of 1 to
1.5 inch hail. Time/location estimated from
radar.
&&
JR/BHLocal storm report, Apr 17, 2:26 PM CDT, 12 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
226 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0201 PM Hail Cumming 41.48N 93.76W
04/17/2026 M1.25 Inch Warren IA Public
Time estimated from radar.
&&
JR/BHLocal storm report, Apr 17, 2:27 PM CDT, 11 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
227 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0225 PM Hail 1 E Knoxville 41.32N 93.08W
04/17/2026 E1.00 Inch Marion IA Emergency Mngr
&&
MDLocal storm report, Apr 17, 2:35 PM CDT, 3 minutes before
Preliminary Local Storm Report
National Weather Service Des Moines IA
235 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0226 PM Hail 3 SSW Mitchellville 41.62N 93.39W
04/17/2026 E1.00 Inch Polk IA Trained Spotter
&&
TRLocal storm report, Apr 17, 2:37 PM CDT, 1 minute before
Preliminary Local Storm Report
National Weather Service Des Moines IA
237 PM CDT Fri Apr 17 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0205 PM Hail 2 NW Cumming 41.50N 93.79W
04/17/2026 E0.50 Inch Warren IA Public
Report from mPING: Half-inch (0.50 in.).
&&
JR/BHThe office that day
Everything else NWS Des Moines, IA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 17, 1:52 PM CDT | Severe Thunderstorm Warning | DMX | Ringgold, Taylor | 38 min |
| Apr 17, 1:57 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marshall, Polk, Story | 48 min |
| Apr 17, 2:01 PM CDT | Severe Thunderstorm Warning | DMX | Dallas, Madison, Polk, Warren | 29 min |
| Apr 17, 2:11 PM CDT | Severe Thunderstorm Warning | DMX | Bremer, Butler, Franklin, Grundy, Hardin | 34 min |
| Apr 17, 2:25 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Mahaska, Marion, Poweshiek | 50 min |
| Apr 17, 2:29 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marshall, Poweshiek, Story, Tama | 46 min |
| Apr 17, 2:33 PM CDT | Tornado Warning | DMX | Jasper, Marshall, Poweshiek, Tama | 42 min |
| Apr 17, 2:35 PM CDT | Severe Thunderstorm Warning | DMX | Bremer, Butler | 40 min |
| Apr 17, 2:44 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Marshall, Poweshiek | 31 min |
| Apr 17, 2:47 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Lucas, Mahaska, Marion, Monroe, Wayne | 43 min |
| Apr 17, 2:57 PM CDT | Severe Thunderstorm Warning | DMX | Clarke, Lucas, Marion, Warren | 11 min |
| Apr 17, 2:59 PM CDT | Severe Thunderstorm Warning | DMX | Decatur, Ringgold, Wayne | 46 min |
| Apr 17, 3:03 PM CDT | Tornado Warning | DMX | Lucas, Marion, Monroe | 11 min |
| Apr 17, 3:07 PM CDT | Severe Thunderstorm Warning | DMX | Marshall, Tama | 38 min |
| Apr 17, 3:10 PM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Marion, Poweshiek | 50 min |
| Apr 17, 3:13 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Monroe, Wayne | 17 min |
| Apr 17, 3:15 PM CDT | Severe Thunderstorm Warning | DMX | Jasper, Poweshiek | 45 min |
| Apr 17, 3:16 PM CDT | Tornado Warning | DMX | Mahaska, Marion, Monroe | 29 min |
| Apr 17, 3:16 PM CDT | Tornado Warning | DMX | Tama | 29 min |
| Apr 17, 3:24 PM CDT | Tornado Warning | DMX | Poweshiek | 39 min |
| Apr 17, 3:26 PM CDT | Severe Thunderstorm Warning | DMX | Mahaska, Monroe, Wapello | 64 min |
| Apr 17, 3:28 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Wayne | 47 min |
| Apr 17, 3:44 PM CDT | Severe Thunderstorm Warning | DMX | Poweshiek, Tama | 31 min |
| Apr 17, 4:01 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Davis, Monroe, Wapello | 44 min |
| Apr 17, 4:02 PM CDT | Severe Thunderstorm Warning | DMX | Poweshiek, Tama | 15 min |
| Apr 17, 4:13 PM CDT | Severe Thunderstorm Warning | DMX | Appanoose, Monroe, Wayne | 32 min |
| Apr 17, 4:17 PM CDT | Tornado Warning | DMX | Davis, Wapello | 28 min |
| Apr 17, 4:26 PM CDT | Severe Thunderstorm Warning | DMX | Wapello | 19 min |
| Apr 17, 4:30 PM CDT | Tornado Warning | DMX | Davis, Wapello | 30 min |
| Apr 17, 6:16 PM CDT | Special Weather Statement | DMX | Polk | 29 min |
Nearby
Tornado Warnings in Iowa, 2026Every tornado warning in 2026Tornadoes in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.