Tornadoes and Flash Flooding in Wisconsin, April 17, 2026

Name: Tornadoes and Flash Flooding in Wisconsin, April 17, 2026
Start: 2026-04-17T15:02
End: 2026-04-17T21:45
Location: Wisconsin

April 17, 2026 · NWS MKX · 36 events in 10 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $31 million
Crop damage: None recorded
Events: 36

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS MKX wrote it up.

A round of severe thunderstorms and flash flooding occurred as a strong cold front approached and tracked across southern WI. More specifically, supercell thunderstorms developed from northeast IA into southwest WI and far southern WI during the late afternoon and evening hours. Eventually these storms transitioned to a squall line which had a number of tornadoes associated with it, as it tracked through southeast Wisconsin. Flash flooding affected much of the same region especially in Janesville. Many large hail reports and a small number of downburst damaging wind reports were also received.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Milwaukee, WI wrote its last area forecast discussion before the first event at Apr 17, 1:44 PM CST, 1 hour 18 minutes earlier. Its key messages:

Thunderstorms with higher-end severe potential and heavy rainfall is expected this afternoon and early evening. An Enhanced Risk (3 out of 5) for severe weather exists over the western half of the CWA. Heavy rain over saturated ground may lead to flash flooding.
A Flood Watch in effect for all of southern Wisconsin until 7am Saturday.
Marine Dense Fog continues through tonight.

Area forecast discussion, Apr 17, 1:44 PM CST, 1 hour 18 minutes before

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
244 PM CDT Fri Apr 17 2026

.KEY MESSAGES...

- Thunderstorms with higher-end severe potential and heavy
  rainfall is expected this afternoon and early evening. An
  Enhanced Risk (3 out of 5) for severe weather exists over the
  western half of the CWA. Heavy rain over saturated ground may
  lead to flash flooding.

- A Flood Watch in effect for all of southern Wisconsin until
  7am Saturday.

- Marine Dense Fog continues through tonight.

&&

.UPDATE...
Issued 244 PM CDT Fri Apr 17 2026

The storms fired along that leading cumulus field that was in
eastern Iowa right around noon. They grew and evolved into a
broken line of supercells and are now tracking a little slower
to the east. The MLCAPE is on the 2000-2500j/kg gradient and the
bulk shear is 40 to 50kt. The significant tornado parameter is
pushing 4 in this region, and the sig hail parameter is 3. These
parameters diminish as the cells congeal into a line over the
next few hours, but wind and line-embedded tornadoes will become
a higher risk.

Radar and satellite are also showing the cold frontal boundary
(just north of Twin Cities to Rochester to just east of Des
Moines) light up with numerous mini supercells. If this initial
round of storms take control for the afternoon, which they are
expected to, this will diminish the intensity of the storms
along the cold front as it tracks across southern WI during the
early evening between 6 and 9 PM. However, if this first round
underperforms, meaning does not produce widespread thunderstorms
(and a cold pool), then the storms along the frontal boundary
will be able to maintain its strength as it moves through.

The other scenario noted in the most recent small-scale model
runs is that the storms along the frontal boundary may
accelerate and catch up to this initial round. The way things
are moving, this seems like a likely scenario. The 18Z HRRR is
hinting at this. This would mean the convection would rush out
ahead of the main front and there will still be a chance for
showers and isolated thunder to linger until that front clears
our area during the overnight hours.

Heavy rain and flash flooding are still a threat due to high
precipitable water and repeated rounds of storms over already-
saturated soil.

Cronce

&&

.SHORT TERM...
Issued 1207 PM CDT Fri Apr 17 2026

Tonight and Saturday:

Nearly all of southern WI has sunshine as of 1130 this morning.
The fog and low stratus are hanging on over east central WI, but
the increasing southerly winds will help that to erode quickly
through the early afternoon. Temperatures are rising quickly,
with areas west of Madison already in the lower 70s. Dewpoints
are rising as well, with lower 60s in the southwest. Gusty winds
are developing as we start to mix out our low layer inversion
and diurnal cu are also popping up. This is all conducive for
priming our environment for convection this afternoon.

The main change for today is that we are expecting storms to
develop and move into southwest WI earlier than forecast, now
between 1 and 5 PM. Storms triggered along a gravity wave just
south of the Twin Cities around 8 am. If we trace that gravity
wave down into Iowa on satellite, the cumulus clouds are
focusing along it. The leading edge of this is now entering
northeast IA and far southeast MN. The timing of it to arrive
in Madison is 230PM/1930Z, give or take a half hour. There is no
lighting in eastern IA yet, but we are watching for that to
happen within the next 30 to 60 minutes.

Whatever develops in IA and tracks eastward is our main show in
southern WI for today. All hazards are on the table. High CAPE,
shear and helicity all point to a large hail (greater than 2
inches), damaging wind and tornado potential. If tornadoes
develop, they would be on the strong side. As any discrete cells
congeal into a line as they head into eastern WI, the severe
threat will be mainly for damaging wind and QLCS tornadoes. With
0 to 3 km shear vectors up to 50 kt and aligned perpendicular
to the line of storms (and streamwise vorticity of 45-50 kt),
brief spin- up tornadoes are favorable along the leading edge
within any notches/bowing line segments.

There is still a chance that the storms that develop in Iowa
could skirt just to the south of WI and be the strongest across
northern IL this afternoon. If I had to guess, the strongest
storms should be over the south half of southern WI. However,
there is still a severe threat for all of WI, including north
central all the way to Green Bay.

The actual cold front is back in south central MN and central
IA. This is a very strong front, with over a 20 degree temp drop
behind it. Storms will be well ahead of the front, but once our
afternoon storms clear, we will still have a chance for
scattered showers and thunderstorms (not severe) until the
actual front passes during the late evening and overnight hours.

Cronce

&&

.LONG TERM...
Issued 244 PM CDT Fri Apr 17 2026

Saturday through Friday:

Gusty west-northwest winds up to 30 mph are expected behind the
cold front Saturday. Sunshine should be prevalent, although
cyclonic flow aloft will allow for some high-level diurnal
cumulus clouds. Saturday highs will only be in the 40s, a stark
contrast to the highs today. Lows Saturday night should dip
below freezing nearly everywhere except the immediate Lake
Michigan lakeshore.

The upper low will remain over Ontario Sunday and a shortwave
trough digging into central and southern WI may steepen lapse
rates enough to produce a few flurries. It looks like moisture
will be very limited with this feature, but the forcing is
certainly there. Highs Sunday will be similar to Saturday but
with slightly lighter northwest winds. Lows Sunday night have a
better chance of dropping below freezing, with lows forecast in
the 25 to 30 degree range.

As high pressure departs the Upper Great Lakes on Monday,
southerly winds will usher milder air back into southern WI.
The sunshine will also help temps get into the mid 50s inland
and lower 50s near the lakeshore. A clipper system will cross
Ontario and Lake Superior Monday night, but southern WI will
remain dry. However, this could push a cold front down Lake
Michigan Tuesday. Not all models have picked up on this
potential yet, so the forecast highs Tue are in the lower 70s
inland and mid 60s lakeshore. Lakeshore temps could end up being
colder, but the highs will depend on when that back door cold
front actually makes it onshore.

There will be a stark temp gradient across southern WI from
west to east on Wednesday as low pressure develops in the
Plains. It looks like the storms associated with the warm front
of this low will be over northeast MN and northern WI Thu. All
We should see temps get back into the upper 70s inland over
southern WI. The next potential for showers and thunderstorms,
potentially severe, looks like next week Friday.

Cronce

&&

.AVIATION...
Issued 1207 PM CDT Fri Apr 17 2026

See the main part of the discussion for thunderstorm chances.
Timing of the storms for southern WI looks earlier than
previously forecast. All severe hazards are possible.

A strong cold front will cross southern WI late tonight. Showers
and a few storms will remain possible until the front clears.
MVFR ceilings are expected behind the front on gusty WNW winds,
and IFR ceilings are possible for a few hours early Saturday
morning. Saturday ceilings should recover to VFR by mid/late
morning and probably scatter out.

Cronce

&&

.MARINE...
Issued 1207 PM CDT Fri Apr 17 2026

Winds will become southerly this morning as a surface low of 29.5
inches approaches from the central plains. Dense fog will
continue over the lake through this evening and likely during
the overnight hours until the cold front clears the lake. This
surface low will quickly move from Omaha to Duluth from this
morning into the afternoon. Winds will become gusty and
southeasterly tonight, and strong to severe storms will cross
the lake as a cold front sweeps through the area. Winds then
become northwesterly behind the cold front Saturday morning.
Breezy northwesterly winds then continue Saturday through Sunday
as the low then races northeast toward Hudson Bay. Winds ease
Monday morning as high pressure tracks southeast over the upper
Great Lakes.

Cronce

&&

.HYDROLOGY...
Issued 1207 PM CDT Fri Apr 17 2026

This afternoon / evening's convection is expected to produce an
additional 0.50 to 1.25 inches of rainfall across the region,
with locally higher totals up to 2.00 inches possible. Probs of
exceeding 2.00 are only 10% or less based off of most guidance.
Highest rainfall potential exists in the western half of the
CWA, given the potential for initial supercells with heavy rain
followed by additional showers / storms along the advancing cold
front (eg. multiple rounds of heavier precip). Further east,
still expecting a good burst of heavy rain from short line
segments or QLCS to be more progressive / fast- moving by that
time of day, but increased the storm total amounts toward an
inch.

Cronce/Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Flood Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-WIZ058-
     WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-
     WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until 7 AM Saturday.

LM...Dense Fog Advisory...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-
     LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-
     LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 4 AM
     Saturday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 PM
     Saturday.

&&

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Hazardous weather outlook, Apr 17, 1:56 PM CST, 1 hour 6 minutes before

Hazardous Weather Outlook
National Weather Service Milwaukee/Sullivan WI
256 PM CDT Fri Apr 17 2026

WIZ046-047-051-052-056>060-062>072-182000-
Marquette-Green Lake-Fond du Lac-Sheboygan-Sauk-Columbia-Dodge-
Washington-Ozaukee-Iowa-Dane-Jefferson-Waukesha-Milwaukee-
Lafayette-Green-Rock-Walworth-Racine-Kenosha-
256 PM CDT Fri Apr 17 2026

This Hazardous Weather Outlook is for portions of east central
Wisconsin, south central Wisconsin and southeast Wisconsin.

.DAY ONE...Rest of Today and Tonight

Thunderstorms with higher-end severe potential and heavy rainfall
is expected this afternoon and early evening. An Enhanced Risk (3
out of 5) for severe weather exists over the western half of the
CWA. Heavy rain over saturated ground may lead to flash flooding.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will be needed through tonight.

LMZ643>646-182000-
Sheboygan to Port Washington WI-
Port Washington to North Point Light WI-
North Point Light to Wind Point WI-
Wind Point WI to Winthrop Harbor IL-
256 PM CDT Fri Apr 17 2026

This Hazardous Weather Outlook is for the nearshore waters from
Sheboygan Wisconsin to Winthrop Harbor Illinois.

.DAY ONE...Tonight

Dense fog continues for the whole nearshore through the overnight
hours.

Small Craft Advisory in effect for high waves and strong
southerly winds through tonight

Thunderstorms are likely late afternoon and this evening, with
severe storms possible.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

Small Craft Advisory will continue through Saturday evening for
breezy west to northwest winds.

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-182000-
Lake Michigan Michigan City IN to St. Joseph MI 5 NM offshore to
mid-line of lake.-
Lake Michigan from Seul Choix Point to Rock Island Passage 5NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and North of a line from Charlevoix MI to South
Fox Island 5NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5NM Offshore to
mid lake-
Lake Michigan from Point Betsie to Manistee MI 5NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI 5NM
offshore to mid lake-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5NM offshore to Mid
Lake-
Lake Michigan from Sheboygan to Port Washington WI 5NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor to Michigan City in 5NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5NM offshore to Mid
lake-
Lake Michigan from St Joseph to South Haven MI 5NM offshore to
Mid Lake-
256 PM CDT Fri Apr 17 2026

This Hazardous Weather Outlook is for the open waters of Lake
Michigan.

.DAY ONE...Tonight

A few southerly gale force gusts are possible through late
evening.

Dense fog continues through tonight.

Thunderstorms are likely late afternoon and this evening, with
severe storms possible.

.DAYS TWO THROUGH SEVEN...Saturday through Friday

No hazardous weather is expected at this time.

MRC

www.weather.gov/mkx

In the hours before

Special weather statement, Apr 17, 2:06 PM CST, 56 minutes before

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
306 PM CDT Fri Apr 17 2026

WIZ046-056-057-172045-
Columbia WI-Marquette WI-Sauk WI-
306 PM CDT Fri Apr 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN COLUMBIA...
SOUTHWESTERN MARQUETTE AND EAST CENTRAL SAUK COUNTIES THROUGH 345 PM
CDT...

At 305 PM CDT, Doppler radar was tracking a strong thunderstorm near
Baraboo, moving northeast at 45 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Baraboo, Portage, Lake Wisconsin, Pardeeville, Packwaukee, Endeavor,
Merrimac, Interstate 90/94 Interchange, Briggsville, Glen Oak, and
Devils Lake St Park.

This includes the following highways...
 Interstate 90/94 between mile markers 98 and 108.
 Interstate 39 between mile markers 85 and 106.
 Interstate 39/90/94 between mile markers 109 and 110.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Tornado Watch remains in effect until 800 PM CDT for south central
Wisconsin.

&&

LAT...LON 4366 8924 4364 8925 4364 8922 4360 8916
      4338 8961 4336 8971 4343 8976 4382 8946
TIME...MOT...LOC 2005Z 218DEG 38KT 4343 8966

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

HEEREN

Special weather statement, Apr 17, 2:08 PM CST, 54 minutes before

Special Weather Statement
National Weather Service Milwaukee/Sullivan WI
308 PM CDT Fri Apr 17 2026

WIZ067-172045-
Lafayette WI-
308 PM CDT Fri Apr 17 2026

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL LAFAYETTE COUNTY THROUGH
345 PM CDT...

At 308 PM CDT, Doppler radar was tracking a strong thunderstorm near
Benton, or 11 miles west of Darlington, moving northeast at 55 mph.

HAZARD...Penny size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vegetation is possible.

Locations impacted include...
Darlington, Shullsburg, Benton, Blanchardville, New Diggings,
Fayette, Lamont, Yellowstone Lake St Park, Calamine, and Lead Mine.

This includes U.S. Highway 151 between mile markers 31 and 32.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Tornado Watch remains in effect until 800 PM CDT for south central
Wisconsin.

&&

LAT...LON 4269 9035 4281 9028 4281 8984 4276 8984
      4251 9024 4251 9035 4255 9043
TIME...MOT...LOC 2008Z 220DEG 47KT 4262 9032

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...<30 MPH

CMILLER

The radar

The Quad Cities radar (KDVN), 120 km away, was scanning. The volume nearest the first event began at 21:04 UTC.

Open the radar archive at this moment

Event by event

15 hail, 12 tornado, 5 flash flood, 3 thunderstorm wind, 1 flood. Local standard time, as filed.

Hail, Lafayette

When: April 17, 3:02 PM CST
Where: Lafayette County, 2 mi W of Seymour Corners
Measured: 1 in hail
Reported by: Public
Coordinates: 42.670, -90.290

Hail, Iowa

When: April 17, 3:07 PM CST
Where: Iowa County, 0.69 mi S of Dodgeville
Measured: 1 in hail
Reported by: Public
Coordinates: 42.960, -90.130

Hail, Iowa

When: April 17, 3:10 PM CST
Where: Iowa County, 0.51 mi E of Dodgeville
Measured: 0.75 in hail
Reported by: Public
Coordinates: 42.970, -90.120

Hail, Lafayette

When: April 17, 3:22 PM CST
Where: Lafayette County, 0.86 mi NW of South Wayne
Measured: 0.75 in hail
Reported by: Public
Coordinates: 42.580, -89.890

Hail, Sauk

When: April 17, 3:40 PM CST
Where: Sauk County, Prairie du Sac Arpt
Measured: 0.75 in hail
Reported by: Public
Coordinates: 43.300, -89.750

Flash Flood, Iowa

When: April 17, 4:00 PM CST to 6:30 PM CST
Where: Iowa County, 3.84 mi ESE of Arena to 2.4 mi ESE of Helena
Cause: Heavy Rain
Property damage: $5,000
Reported by: 911 Call Center
Coordinates: 43.157, -89.846

Flash flooding of creeks flowing over several rural roads. This included a flooded road in Cobb, floodwaters over bridges on Amacher Hollow Rd. and Sawle Rd.

Hail, Green

When: April 17, 4:11 PM CST
Where: Green County, 1.23 mi NW of Monroe
Measured: 1.25 in hail
Reported by: Public
Coordinates: 42.610, -89.650

Hail, Green

When: April 17, 4:20 PM CST
Where: Green County, 0.47 mi W of Monroe
Measured: 2.75 in hail
Reported by: Public
Coordinates: 42.600, -89.639

Hail, Green

When: April 17, 4:20 PM CST
Where: Green County, 0.87 mi SW of Monroe
Measured: 1.5 in hail
Reported by: Public
Coordinates: 42.590, -89.640

Thunderstorm Wind, Dodge

When: April 17, 4:42 PM CST to 4:45 PM CST
Where: Dodge County, 0.85 mi NW of Richwood
Measured: 56 kt (64 mph) estimated gust
Property damage: $15,000
Reported by: Public
Coordinates: 43.240, -88.780

A barn wall was blown down.

Flash Flood, Green

When: April 17, 5:00 PM CST to 7:00 PM CST
Where: Green County, 3.73 mi SSW of Albany to 2.59 mi SSE of Albany
Cause: Heavy Rain
Property damage: $5,000
Reported by: 911 Call Center
Coordinates: 42.648, -89.448

Flash flooding of creeks leading to flooded roads at the intersection of County Highway F and FF, and State Highway 104 north of Brodhead.

Tornado, Rock

When: April 17, 5:02 PM CST to 5:05 PM CST
Where: Rock County, 1.93 mi NNW of Tiffany to 3.28 mi W of Avalon
Rating: EF1
Path length: 1.89 mi
Path width: 75 yd
Property damage: $408,000
Reported by: NWS Storm Survey
Coordinates: 42.606, -88.943

Brief tornado that caused damage near Maple Lane southeast of Janesville. Storm chaser video confirmed a brief tornado in this area. More widespread damage occurred west and east of this track due to downburst winds.

Tornado, Rock

When: April 17, 5:05 PM CST to 5:10 PM CST
Where: Rock County, 1.84 mi SW of Emerald Grove to 1.05 mi SE of Emerald Grove
Rating: EF1
Path length: 2.06 mi
Path width: 100 yd
Property damage: $215,000
Reported by: NWS Storm Survey
Coordinates: 42.649, -88.903

Brief tornado went through Emerald Grove, destroying a barn and causing damage to an antique store. Significant tree damage along the path as well with debris lofted well to the ENE from the structures.

Hail, Rock

When: April 17, 5:12 PM CST
Where: Rock County, 0.51 mi W of Downtown Janesville
Measured: 1.5 in hail
Reported by: Public
Coordinates: 42.680, -89.030

Tornado, Rock

When: April 17, 5:15 PM CST to 5:20 PM CST
Where: Rock County, 1.95 mi SSW of Johnstown Center to 2.83 mi SE of Johnstown
Rating: EF1
Path length: 3.3 mi
Path width: 75 yd
Continued into: Walworth, Wi (MKX)
Property damage: $124,000
Reported by: NWS Storm Survey
Coordinates: 42.673, -88.842

Multivortex tornado documented southwest of Richmond. Multiple sheds with sheet metal damage along County Highway M before entering Walworth County.

Flash Flood, Rock

When: April 17, 5:15 PM CST to 8:45 PM CST
Where: Rock County, 2.94 mi WSW of Downtown Janesville to 2.56 mi ESE of Leyden
Cause: Heavy Rain
Property damage: $30 million
Reported by: Law Enforcement
Coordinates: 42.669, -89.076

Around 700 911 calls mainly attributed to flash flooding. Flash flooding of streets and yards in Janesville with basement flooding in many homes. Many vehicles stranded in deep water. A bridge was washed out due to the flooding of Fisher Creek over Rockport Rd. Severe flooding of a church, and the basement of an elementary school. The school's mechanical systems and main power panel were destroyed. The school has been closed. RAJ stadium flooded. A train derailment in downtown Janesville with 3 locomotives off the tracks, due to a sinkhole. 1st responders conducted a water rescue of the engineer using a rope.

Hail, Rock

When: April 17, 5:16 PM CST
Where: Rock County, 0.51 mi E of Beloit
Measured: 1.75 in hail
Reported by: Public
Coordinates: 42.520, -89.020

Tornado, Walworth

When: April 17, 5:20 PM CST to 5:21 PM CST
Where: Walworth County, 3.97 mi SW of Richmond to 3.43 mi SSW of Richmond
Rating: EF1
Path length: 1.07 mi
Path width: 75 yd
Property damage: $124,000
Reported by: NWS Storm Survey
Coordinates: 42.674, -88.777

Multivortex tornado documented southwest of Richmond. Multiple sheds with sheet metal damage along County Highway M before entering Walworth County.

Hail, Rock

When: April 17, 5:23 PM CST
Where: Rock County, 0.69 mi N of Milton
Measured: 1.75 in hail
Reported by: Public
Coordinates: 42.780, -88.950

Hail, Rock

When: April 17, 5:29 PM CST
Where: Rock County, 0.51 mi E of Beloit
Measured: 2 in hail
Reported by: Public
Coordinates: 42.520, -89.020

Tornado, Walworth

When: April 17, 5:39 PM CST to 5:46 PM CST
Where: Walworth County, 2.74 mi NNW of Darien to 1.9 mi W of Delavan
Rating: EF1
Path length: 2.81 mi
Path width: 75 yd
Property damage: $133,000
Reported by: NWS Storm Survey
Coordinates: 42.636, -88.722

The tornado appeared to start north of School Section Rd and west of Old 89 Rd with mainly tree damage going to the east-northeast. The tornado then tracked along State Road 11 going east toward Delavan. About 4 farmsteads had damage to them, including one empty silo that was blown down from about halfway up. The tornado then continued east-southeast along Hwy 11 and ended near Redwood Ct on the west side of Delavan where it caused some tree damage.

Tornado, Walworth

When: April 17, 5:43 PM CST to 5:46 PM CST
Where: Walworth County, 3.36 mi WNW of Delavan to 2.25 mi WNW of Delavan Lake
Rating: EF1
Path length: 2.71 mi
Path width: 75 yd
Property damage: $99,000
Reported by: NWS Storm Survey
Coordinates: 42.651, -88.690

Tornado appeared to begin along Turtle Creek west of Klug Rd and south of County Road M. The tornado destroyed an open facing barn shed along Klug Rd. It then tracked to the northeast and caused damage to 3 barns, a garage and a house along County Road P. It then continued to the northeast and crossed Dam Rd before ending near Turtle Creek again.

Flood, Dodge

When: April 17, 6:00 PM CST to 9:00 PM CST
Where: Dodge County, 1.99 mi NE of Rubicon to 1.98 mi ENE of Rubicon
Cause: Heavy Rain
Property damage: $5,000
Reported by: 911 Call Center
Coordinates: 43.348, -88.439

Flooding of Butler Creek flowing over a bridge on County Highway N.

Hail, Walworth

When: April 17, 6:02 PM CST
Where: Walworth County, 1.52 mi W of Little Prairie
Measured: 1 in hail
Reported by: Public
Coordinates: 42.830, -88.560

Hail, Waukesha

When: April 17, 6:12 PM CST
Where: Waukesha County, Eagle
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 42.880, -88.470

Tornado, Walworth

When: April 17, 6:22 PM CST to 6:25 PM CST
Where: Walworth County, 1.96 mi N of Lyons Arpt to 2.08 mi ENE of Lyons Arpt
Rating: EF0
Path length: 1.81 mi
Path width: 50 yd
Property damage: $4,000
Reported by: NWS Storm Survey
Coordinates: 42.698, -88.366

The tornado began along Spring Prairie Rd and moved to the southeast. The tornado had an intermittent path with a few trees uprooted, some shingles peeled from the south side of a roof, another roof peeled back on the southeast corner, and siding damage to a garage. The track continued to the southeast with several limbs snapped from the tops of trees, ending near Old County Highway DD north of Highway 11.

Thunderstorm Wind, Walworth

When: April 17, 6:22 PM CST to 6:24 PM CST
Where: Walworth County, 0.69 mi N of East Troy
Measured: 56 kt (64 mph) estimated gust
Property damage: $1,000
Reported by: Public
Coordinates: 42.790, -88.400

An uprooted tree.

Hail, Waukesha

When: April 17, 6:25 PM CST
Where: Waukesha County, 2.07 mi S of Eagle
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 42.850, -88.470

Tornado, Racine

When: April 17, 6:32 PM CST to 6:36 PM CST
Where: Racine County, 1.47 mi SSW of Caldwell to 1.51 mi SE of Caldwell
Rating: EF0
Path length: 1.42 mi
Path width: 50 yd
Property damage: $6,000
Reported by: NWS Storm Survey
Coordinates: 42.810, -88.278

Tornado started in a mainly open field to the west of Highway 83. A few branches were downed. Along the intermittent path, multiple trees were downed in different directions. A port-a-potty was displaced and pushed over. The tornado continued to the northeast into an inaccessible field.

Tornado, Waukesha

When: April 17, 6:52 PM CST to 6:55 PM CST
Where: Waukesha County, 1.81 mi SW of Muskego Lake to 1.2 mi SW of Muskego Lake
Rating: EF0
Path length: 0.62 mi
Path width: 70 yd
Property damage: $5,000
Reported by: NWS Storm Survey
Coordinates: 42.855, -88.149

The tornado began over a farm field where a few small limbs were downed. The tornado continued to the northeast, snapping a few trees and downing several large limbs. Further to the northeast, the view was not accessible with the tornado ending southwest of Big Muskego Lake, south of the Big Muskego Lake Wildlife area.

Tornado, Racine

When: April 17, 6:55 PM CST to 7:00 PM CST
Where: Racine County, 0.7 mi NNW of North Cape to 1.78 mi WNW of Kneeland
Rating: EF0
Path length: 3.45 mi
Path width: 50 yd
Property damage: $17,000
Reported by: NWS Storm Survey
Coordinates: 42.790, -88.073

Tornado started near Raynor Ave and tracked to the northeast while crossing 5 Mile and 6 Mile Rd before ending near 7 Mile Rd. Most damage was minor but some sheet metal was lofted from a barn. Tornado tracked just to the east of the Milwaukee Airport Terminal Doppler Radar.

Tornado, Racine

When: April 17, 6:56 PM CST to 7:00 PM CST
Where: Racine County, 1.03 mi ESE of Franksville Hunts Ar to 1.82 mi NNW of Kneeland
Rating: EF1
Path length: 3.89 mi
Path width: 75 yd
Continued into: Milwaukee, Wi (MKX)
Property damage: $105,000
Reported by: NWS Storm Survey
Coordinates: 42.815, -88.081

Tornado started near 6 Mile Rd west of Raynor Ave and tracked to the northeast, ending in southern Milwaukee county. Possible that this tornado merged with the other one directly to the south.

Tornado, Milwaukee

When: April 17, 7:00 PM CST to 7:05 PM CST
Where: Milwaukee County, 1.95 mi SSW of Franklin Arpt to 1.36 mi SSE of Franklin Arpt
Rating: EF1
Path length: 1.31 mi
Path width: 75 yd
Property damage: $105,000
Reported by: NWS Storm Survey
Coordinates: 42.844, -88.015

Tornado started near 6 Mile Rd west of Raynor Ave and tracked to the northeast, ending in southern Milwaukee county. Possible that this tornado merged with the other one directly to the south.

Flash Flood, Milwaukee

When: April 17, 7:10 PM CST to 9:45 PM CST
Where: Milwaukee County, 1.73 mi S of Butler to 1.97 mi SSE of Franklin
Cause: Heavy Rain
Reported by: Social Media
Coordinates: 43.055, -88.066

Numerous social media videos depicting street flooding throughout the county.

Thunderstorm Wind, Racine

When: April 17, 7:11 PM CST to 7:13 PM CST
Where: Racine County, 0.69 mi N of Caddy Vista
Measured: 70 kt (81 mph) estimated gust
Property damage: $30,000
Reported by: NWS Storm Survey
Coordinates: 42.840, -87.920

Total destruction of a greenhouse and damage to other outbuildings. Multiple trees uprooted and leaning to the north northeast.

Flash Flood, Racine

When: April 17, 7:30 PM CST to 9:00 PM CST
Where: Racine County, 1.77 mi SSE of Sturtevant Sylvania to 2.64 mi E of Browns Lake
Cause: Heavy Rain
Property damage: $2,000
Reported by: 911 Call Center
Coordinates: 42.675, -87.962

Flash flooding of streets from the 1600 to 1700 block of 2 Mile Rd. Flash flooding at the 1000 block of 61st Dr. Flooding at 67th Dr. and Mill Ave. Flash flooding at Sharp Rd. and Rowntree Rd.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Wisconsin in 2026 Every state in 2026 This day in weather history The tornado archive for Wisconsin, 2026 Warnings in Wisconsin, April 2026

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1334126, 1334105, 1334106, 1334110, 1334111, 1334146, 1334119, 1334129, 1334131, 1334095, 1334147, 1329343, 1329344, 1334114, 1329348, 1334155, 1334133, 1329349, 1334112, 1334134, 1329350, 1329352, 1334151, 1334118, 1334115, 1329355, 1334098, 1334117, 1329356, 1329358, 1329361, 1329362, 1329363, 1334157, 1334103, 1335051.