Hail and Damaging Winds in Wisconsin, April 18, 2002

Name: Hail and Damaging Winds in Wisconsin, April 18, 2002
Start: 2002-04-18T12:54
End: 2002-04-18T22:03
Location: Wisconsin

April 18, 2002 · NWS MKX · 49 events in 18 counties and zones

Where it happened

Every event with a place to put it; 6 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: $308,000
Crop damage: None recorded
Events: 49

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.

Severe storms, with large hail and damaging, straight-line, downburst winds, developed ahead and along a cold front, which plowed east into an unseasonably warm, moist airmass over southern Wisconsin. Maximum afternoon temperatures were mostly in the 80s (about 30 to 35 degrees above normal) during the 4-day period of April 15-18. The hail stones ranged from 3/4 inch to 2 inches in diameter, resulting in several vehicles receiving dents (in Lafayette, Sauk, and Dane County). The damaging winds were mostly in the 60 to 70 mph range resulting in numerous reports of uprooted trees. Dozens of power lines were pulled down as broken tree branches fell on them. About 25,000 customers lost electrical power, based on utility company records. The areas with the largest amount of tree damage were: 1) from Graitiot to Woodford in Lafayette Co., 2) from northwest of Browntown to Monroe in Green Co., and 3) from Watertown to Mayville in Dodge Co. Otherwise, tree damage due to wet microbursts was scattered. A semi-trailer northeast of Beloit on Interstate 90 sustained damage when it was blown over by the powerful thunderstorm winds. Just west-southwest of Brodhead, a shed was blown down. In the area northwest of Browntown to Monroe, a barn was blown down, a shed was blown on to a home, and two residential roofs were damaged by broken tree limbs. A shed under construction at the Watertown High School in Dodge County was damaged by the powerful winds. A wind-toppled tree damaged a vehicle near Silver Lake (Kenosha Co.). Lightning started a 75 acre grass fire in the Horicon Marsh in Dodge County, a 1 acre grass fire south of Ft. Atkinson in Jefferson County, and a 5 acre grass fire south of Portage in Columbia County. Elsewhere, separate lightning strikes started fires which damaged the roof of two Madison (Dane Co.) homes. Several of the thunderstorms had mesocyclones,and cloud-base rotation was noted by severe weather spotters, however there were no tornado reports.

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 18, 10:20 AM CST, 2 hours 34 minutes earlier.

Area forecast discussion, Apr 18, 10:20 AM CST, 2 hours 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1120 AM CDT THU APR 18 2002

FORECAST FOCUS IS ON SEVERE POTENTIAL THIS AFTERNOON AHEAD OF
APPROACHING CDFNT.

LINE OF DEVELOPING THUNDERSTORMS JUST AHEAD OF NOSE OF LOW LEVEL
JET.  SOUNDINGS SHOW LOW LEVEL CAP IN PLACE AT THIS MOMENT...BUT
FORECAST SOUNDINGS SHOW CAP TO RAPIDLY DISSIPATE...SO THIS LINE MAY
RAPIDLY INTENSIFY OVER SOUTHCENTRAL WI EARLY THIS AFTERNOON.  CAPES
RISE TO OVER 2000 J/KG.  FLOW IS RATHER UNIDIRECTIONAL NOW...BUT ANY
LAKE BREEZE FRONT WOULD PRODUCE MODERATE HELICITIES...AND EHI VALUES
TO NEAR 3...SO BOUNDAIES WILL NEED TO BE WATCHED CLOSELY. DEW POINTS
ALREADY IN LOWER 60S...WITH MID 60S ALREADY OVER N IL.

MAIN COLD FRONT DOES NOT COME THROUGH SE WI UNTIL AFTER
MIDNIGHT...AND MODELS SHOW WEAK MID LEVEL TROUGH THAT MAY PRODUCE
ANOTHER LINE OF THUNDERSTORMS THIS EVENING.

VERY COOL HIGH PRESSURE BUILDS OVER CWA AFTER EXIT OF CDFNT. QUITE A
CHG AFTER RECENT RECORD HEAT.

.MKX...NONE.

HENTZ

In the hours before

Special weather statement, Apr 18, 10:42 AM CST, 2 hours 12 minutes before

WIZ046-047-051-052-056>060-062>072-181930-

SPECIAL WEATHER STATEMENT...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1142 AM CDT THU APR 18 2002

...HAZARDOUS WEATHER OUTLOOK FOR EMERGENCY PLANNERS...
...FOR SOUTH CENTRAL AND SOUTHEAST WISCONSIN...

THREAT...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING FOR SOUTH CENTRAL AND SOUTHEAST WISCONSIN.

DISCUSSION...A STRONG FLOW OF WARM MOIST AIR IN THE MIDDLE AND LOWER
LEVELS OF THE ATMOSPHERE...WILL INCREASE INSTABILITY OVER SOUTHERN
WISCONSIN FROM WEST TO EAST THIS AFTERNOON. AN APPROACHING COLD
FRONT WILL INCREASE LOW LEVEL CONVERGENCE...HELPING TO TRIGGER
THUNDERSTORMS THIS AFTERNOON AND EVENING.

FORECAST ENVIRONMENTAL FACTORS INDICATE LINES OF THUNDERSTORMS WITH
HIGH WINDS AND LARGE HAIL...WITH ISOLATED TORNADOES POSSIBLE THIS
AFTERNOON AND EVENING.

OUTLOOK FOR FRIDAY...SCATTERED SHOWERS ARE EXPECTED AFTER THE COLD
FRONT PASSES THROUGH SOUTHERN WISCONSIN OVERNIGHT...WITH NO SEVERE
THUNDERSTORMS.

SPOTTER ACTIVATION...
STORM SPOTTER GROUPS WILL BE NEEDED THIS AFTERNOON AND EVENING.

STAY TUNED TO NOAA WEATHER RADIO...AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES. CHECK OUR WEB SITE AT HTTP://WWW.CRH.NOAA.GOV/MKX

REM

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

22 hail, 21 thunderstorm wind, 5 lightning, 1 funnel cloud. Local standard time, as filed.

Hail, Marquette

When: April 18, 12:54 PM CST
Where: Marquette County, 4 mi E of Oxford
Measured: 0.75 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 43.783, -89.483

Hail, Lafayette

When: April 18, 2:15 PM CST
Where: Lafayette County, 3 mi NW of Belmont
Measured: 1 in hail
Property damage: $500
Reported by: TRAINED SPOTTER
Coordinates: 42.767, -90.383

Lightning, Columbia

When: April 18, 2:15 PM CST
Where: Columbia County, 3 mi S of Portage
Reported by: NEWSPAPER
Coordinates: 43.467, -89.334 (the zone’s center; the record gives no point)

Hail, Lafayette

When: April 18, 2:17 PM CST
Where: Lafayette County, Belmont
Measured: 1.75 in hail
Property damage: $3,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.733, -90.333

Hail, Iowa

When: April 18, 2:38 PM CST
Where: Iowa County, 1 mi S of Mineral Pt
Measured: 0.88 in hail
Reported by: EMERGENCY MANAGER
Coordinates: 42.833, -90.183

Hail, Sauk

When: April 18, 3:00 PM CST
Where: Sauk County, Merrimac
Measured: 1 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 43.367, -89.617

Hail, Sauk

When: April 18, 3:00 PM CST
Where: Sauk County, Prairie du Sac
Measured: 0.88 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 43.283, -89.717

Hail, Columbia

When: April 18, 3:09 PM CST
Where: Columbia County, Portage
Measured: 1 in hail
Reported by: AMATEUR RADIO
Coordinates: 43.550, -89.450

Thunderstorm Wind, Sauk

When: April 18, 3:15 PM CST
Where: Sauk County, 3 mi E of Baraboo
Measured: 61 kt (70 mph)
Reported by: NEWSPAPER
Coordinates: 43.467, -89.667

Hail, Columbia

When: April 18, 3:20 PM CST
Where: Columbia County, 5 mi NNE of Okee
Measured: 1 in hail
Reported by: EMERGENCY MANAGER
Coordinates: 43.417, -89.550

Hail, Sauk

When: April 18, 3:33 PM CST
Where: Sauk County, Merrimac
Measured: 1.75 in hail
Property damage: $2,000
Reported by: LAW ENFORCEMENT
Coordinates: 43.367, -89.617

Lightning, Jefferson

When: April 18, 3:40 PM CST
Where: Jefferson County, 3 mi S of Ft Atkinson
Reported by: NEWSPAPER
Coordinates: 43.021, -88.776 (the zone’s center; the record gives no point)

Hail, Marquette

When: April 18, 3:53 PM CST
Where: Marquette County, Endeavor
Measured: 0.75 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 43.700, -89.467

Hail, Dane

When: April 18, 4:00 PM CST
Where: Dane County, Madison
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 43.067, -89.417

Lightning, Dane

When: April 18, 4:00 PM CST
Where: Dane County, Madison
Property damage: $5,000
Reported by: NEWSPAPER
Coordinates: 43.067, -89.418 (the zone’s center; the record gives no point)

Hail, Dane

When: April 18, 4:10 PM CST
Where: Dane County, 1 mi SW of (Msn)truax Fld Madis
Measured: 1 in hail
Reported by: AMATEUR RADIO
Coordinates: 43.117, -89.350

Hail, Dane

When: April 18, 4:10 PM CST
Where: Dane County, 1 mi SW of Madison
Measured: 1 in hail
Reported by: AMATEUR RADIO
Coordinates: 43.050, -89.433

Funnel Cloud, Rock

When: April 18, 4:15 PM CST
Where: Rock County, 2 mi NE of Clinton
Reported by: FIRE DEPT/RESCUE SQUAD
Coordinates: 42.671, -89.072 (the zone’s center; the record gives no point)

Lightning, Dane

When: April 18, 4:22 PM CST
Where: Dane County, Madison
Property damage: $5,000
Reported by: NEWSPAPER
Coordinates: 43.067, -89.418 (the zone’s center; the record gives no point)

Thunderstorm Wind, Rock

When: April 18, 4:25 PM CST
Where: Rock County, Milton
Measured: 57 kt (66 mph)
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 42.767, -88.950

Hail, Dane

When: April 18, 4:29 PM CST
Where: Dane County, Madison
Measured: 0.88 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 43.067, -89.417

Hail, Green Lake

When: April 18, 4:34 PM CST to 4:39 PM CST
Where: Green Lake County, Berlin
Measured: 0.75 in hail
Reported by: EMERGENCY MANAGER
Coordinates: 43.967, -88.933

Hail, Dane

When: April 18, 4:35 PM CST
Where: Dane County, Monona
Measured: 0.75 in hail
Reported by: AMATEUR RADIO
Coordinates: 43.067, -89.317

Hail, Rock

When: April 18, 6:00 PM CST
Where: Rock County, Evansville
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 42.783, -89.300

Hail, Dane

When: April 18, 6:30 PM CST
Where: Dane County, Deerfield
Measured: 2 in hail
Property damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 43.050, -89.067

Thunderstorm Wind, Iowa

When: April 18, 6:36 PM CST
Where: Iowa County, 2 mi W of Highland
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.050, -90.417

Hail, Rock

When: April 18, 6:40 PM CST
Where: Rock County, Janesville
Measured: 0.75 in hail
Reported by: LAW ENFORCEMENT
Coordinates: 42.683, -89.017

Hail, Rock

When: April 18, 6:44 PM CST to 6:47 PM CST
Where: Rock County, Johnstown
Measured: 0.75 in hail
Reported by: AMATEUR RADIO
Coordinates: 42.700, -88.817

Thunderstorm Wind, Marquette

When: April 18, 7:37 PM CST
Where: Marquette County, Briggsville
Measured: 52 kt (60 mph)
Reported by: AMATEUR RADIO
Coordinates: 43.650, -89.583

Thunderstorm Wind, Iowa

When: April 18, 7:58 PM CST
Where: Iowa County, Dodgeville
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.967, -90.133

Thunderstorm Wind, Columbia

When: April 18, 8:05 PM CST
Where: Columbia County, Poynette
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.400, -89.400

Hail, Green Lake

When: April 18, 8:10 PM CST
Where: Green Lake County, 5 mi SSW of Green Lake
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 43.767, -88.983

Thunderstorm Wind, Dodge

When: April 18, 8:23 PM CST
Where: Dodge County, Beaver Dam
Measured: 53 kt (61 mph)
Reported by: AMATEUR RADIO
Coordinates: 43.467, -88.833

Thunderstorm Wind, Lafayette

When: April 18, 8:30 PM CST to 8:50 PM CST
Where: Lafayette County, Gratiot
Measured: 56 kt (64 mph)
Reported by: EMERGENCY MANAGER
Coordinates: 42.583, -90.017

Thunderstorm Wind, Dane

When: April 18, 8:32 PM CST
Where: Dane County, Middleton
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.100, -89.500

Thunderstorm Wind, Fond du Lac

When: April 18, 8:37 PM CST
Where: Fond du Lac County, Waupun
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.633, -88.733

Thunderstorm Wind, Dodge

When: April 18, 8:37 PM CST
Where: Dodge County, Waupun
Measured: 52 kt (60 mph)
Reported by: TRAINED SPOTTER
Coordinates: 43.633, -88.733

Thunderstorm Wind, Dodge

When: April 18, 8:40 PM CST to 8:45 PM CST
Where: Dodge County, Watertown
Measured: 52 kt (60 mph)
Property damage: $55,000
Reported by: NEWSPAPER
Coordinates: 43.200, -88.717

Lightning, Dodge

When: April 18, 8:40 PM CST
Where: Dodge County, 4 mi NE of Horicon
Reported by: NEWSPAPER
Coordinates: 43.416, -88.707 (the zone’s center; the record gives no point)

Thunderstorm Wind, Jefferson

When: April 18, 8:45 PM CST
Where: Jefferson County, Lake Mills
Measured: 51 kt (59 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 43.083, -88.900

Thunderstorm Wind, Green

When: April 18, 8:45 PM CST to 8:55 PM CST
Where: Green County, 5 mi NNW of Browntown
Measured: 61 kt (70 mph)
Property damage: $200,000
Reported by: NEWSPAPER
Coordinates: 42.650, -89.850

Thunderstorm Wind, Green

When: April 18, 9:02 PM CST
Where: Green County, 1 mi WSW of Brodhead
Measured: 56 kt (64 mph)
Property damage: $15,000
Reported by: NEWSPAPER
Coordinates: 42.617, -89.383

Hail, Sheboygan

When: April 18, 9:11 PM CST
Where: Sheboygan County, Greenbush
Measured: 0.75 in hail
Reported by: AMATEUR RADIO
Coordinates: 43.783, -88.083

Thunderstorm Wind, Rock

When: April 18, 9:14 PM CST to 9:22 PM CST
Where: Rock County, (Jvl)rock Co Arpt Ja
Measured: 55 kt (63 mph)
Property damage: $10,000
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 42.617, -89.033

Thunderstorm Wind, Washington

When: April 18, 9:15 PM CST
Where: Washington County, West Bend
Measured: 52 kt (60 mph)
Property damage: $3,000
Reported by: NEWSPAPER
Coordinates: 43.417, -88.183

Thunderstorm Wind, Walworth

When: April 18, 9:25 PM CST
Where: Walworth County, Whitewater
Measured: 52 kt (60 mph)
Reported by: AMATEUR RADIO
Coordinates: 42.833, -88.733

Thunderstorm Wind, Milwaukee

When: April 18, 9:32 PM CST
Where: Milwaukee County, Brown Deer
Measured: 53 kt (61 mph)
Reported by: AMATEUR RADIO
Coordinates: 43.167, -87.967

Thunderstorm Wind, Racine

When: April 18, 9:57 PM CST
Where: Racine County, Burlington
Measured: 52 kt (60 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 42.667, -88.267

Thunderstorm Wind, Kenosha

When: April 18, 10:03 PM CST
Where: Kenosha County, 1 mi NNE of Silver Lake
Measured: 52 kt (60 mph)
Property damage: $4,000
Reported by: LAW ENFORCEMENT
Coordinates: 42.567, -88.167

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Lightning: A lightning strike that killed, injured or caused damage.
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.
Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.

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

The same day elsewhere

Every storm in Wisconsin in 2002 Every state in 2002 This day in weather history Warnings in Wisconsin, April 2002

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: 5289632, 5289243, 5289248, 5289244, 5289242, 5289245, 5289246, 5289247, 5289252, 5289253, 5289357, 5289722, 5289359, 5289249, 5289251, 5289250, 5289739, 5289360, 5289361, 5289358, 5289362, 5289737, 5289363, 5289365, 5289364, 5289735, 5289366, 5289367, 5289631, 5289630, 5289636, 5289633, 5289723, 5289738, 5289634, 5289635, 5289724, 5289725, 5289726, 5289637, and more.