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Iron Ridge Tornado

(Dodge County)

June 1, 2000

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...Here is a Summary of the Severe Weather Event on June 1, 2000...

In the morning hours, a surface low was situated over Southwest 
Minnesota, trailing a cold front across the Central Plains. A warm 
front also extended southeast towards the southern tip of Lake 
Michigan. Very warm and unstable air was located to the south of 
the warm front while cooler and more stable air was found to the 
north of the warm front. Strong southerly winds transporting 
moisture from the Gulf of Mexico pushed over the warm front 
helping to generate strong lifting across Minnesota and 
Wisconsin, which led to widespread morning showers and 
thunderstorms. These thunderstorms were not severe but 
acted to produce moderate to heavy rainfall at times. 2.00 
inches of rainfall were reported at Eau Claire between 7 AM 
and 1 PM.

Meanwhile, through much of the morning and early afternoon, 
the surface low continued to strengthen as it moved northeast 
into Northwest Wisconsin. Strong southerly winds continued across 
Iowa and Illinois, helping to push the warm front north into central 
Wisconsin by the afternoon. Temperatures and dew points increased 
dramatically across Southern Wisconsin with the passage of the 
front. Clouds began to break up, allowing the sun to heat the 
surface and causing the atmosphere to become very unstable. 
Strong southerly winds at the surface and a west-southwesterly 
jet stream aloft increased the vertical wind shear across 
Wisconsin. The area was set for a severe weather event and at 
11:30 AM the Storm Prediction Center upgraded Southern Wisconsin 
to a Moderate Risk of severe weather. Between 1 PM and 2 PM 
thunderstorms started developing in Southeast Minnesota and 
Northern Iowa.

Around 2 PM, the Storm Prediction Center issued a Tornado Watch 
for all of southern Wisconsin and part of Central Wisconsin that 
was valid until 8 PM. The thunderstorms in Minnesota and Iowa 
interacted with the high-shear environment to quickly become 
supercells as they entered Western Wisconsin. One supercell 
caused a string of extremely severe weather from Monroe County 
beginning around 3 PM into Juneau County around 4:30 PM. Two F1 
tornadoes spun up as a result of the supercell (link to 
La Crosse site). In addition the supercell 
produced extremely damaging winds and very large hail. 
Softball sized hail, or hail with a diameter of 4.5 inches, was 
reported in Monroe County 4 miles southeast of Oakdale. Wind 
gusts of 90 to 100 mph were reported between 4:03 PM and 4:18 PM 
in Juneau County. Volk Field recorded a 94-mile per hour gust in this 
time frame. Additional thunderstorms caused some severe weather 
across the remainder of Western Wisconsin.

Shortly before 5 PM a solid line of thunderstorms began to push 
into the Milwaukee/Sullivan County Warning Area (CWA), entering 
Sauk and Marquette Counties. Winds were estimated to be 80 miles 
per hour in Briggsville in Marquette County. Trees were downed in 
Sauk County as well, but the major story was heavy rainfall as 
3.75 inches of rain fell in North Freedom in 45 minutes. By 
5:45 PM the line of thunderstorms grew in length mainly to the 
south where new thunderstorm cells were merging with the initial 
line. The line extended from near Brandon to Beaver Dam to Sauk 
City to Platteville to Dubuque. Severe bowing was noted in Northern 
Dodge County, the location of strong atmospheric rotation. This 
section of the line produced the F2 tornado that caused major 
damage in Iron Ridge in Dodge County between 5:06 and 5:25 PM. 
An F1 tornado was reported in Lafayette County between 5:02 to 
5:03 PM. Additional funnel clouds and weak F0 tornadoes were 
reported up and down the line of storms in the Sullivan CWA.

Wind damage was noted across the remainder of the Sullivan 
CWA through the early evening hours as the line progressed 
across the area. Winds continued to gust to nearly 80 miles per 
hour through the Madison area, which ripped roof shingles off 
of homes and downed trees, blocking many roads in the city. 
Flooding was also a major problem. In the weeks before the 
storm, a quasi-stationary boundary had been oscillating near 
Southern Wisconsin, which had allowed for very heavy rainfall 
totals in the month of May. Several rounds of thunderstorms on 
the 1st had produced even more excessive rainfall, causing flash 
flooding and some rivers and creeks to rise above their banks.

The thunderstorms exited Southern Wisconsin over Lake Michigan 
and continued to cause widespread wind damage across the Lower 
Peninsula of Michigan generally after 8:45 PM Central Daylight 
Time. In all, 67 damaging wind reports were received across the 
Upper Midwest and Great Lakes on June 1st with the highest 
concentration of reports from Wisconsin and Northern Illinois 
into Lower Michigan.


PUBLIC INFORMATION STATEMENT...UPDATED
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
1215 PM CDT WED JUNE 7 2000

...2nd PRELIMINARY REPORT FOR JUNE 1st IRON RIDGE TORNADO...

A TORNADO STRUCK THE EASTCENTRAL PART OF DODGE COUNTY AND EXTREME WEST CENTRAL 
PART OF WASHINGTON COUNTY DURING THE EVENING OF JUNE 1ST.  IT TRAVELED RIGHT 
THROUGH THE VILLAGE OF IRON RIDGE. THIS TORNADO WAS RATED F2 WITH A TOTAL PATH 
LENGTH OF 16.4 MILES AND MAXIMUM WIDTH OF 100 YARDS.  AN F2 TORNADO HAS WINDS OF 
113 TO 157 MPH. THE IRON RIDGE TORNADO PROBABLY HAD WINDS OF 140 TO 150 MPH.

THIS TORNADO DESTROYED 6 RESIDENTIAL HOMES AND DAMAGED 26 OTHERS. IT DAMAGED 6 
BUSINESSES. IT DESTROYED 5 AGRICULTURAL BUILDINGS AND DAMAGED 2 OTHERS. THERE 
WERE NO INJURIES OR DEATHS.  IN ADDITION...A SILO WAS DAMAGED...A CONSTUCTION 
TRAILER WAS OVERTURNED...AND MANY TREES UPROOTED OR SNAPPED OFF.  MONETARY VALUE
FOR THE DAMAGE...CLEAN UP...AND PROTECTIVE MEASURES IS ABOUT 1.1 MILLION. 

THE TORNADO SPUN UP AT 606 PM CDT JUST TO THE NORTH OF SINISSIPPI LAKE ABOUT 4 
MILES SOUTH OF THE CENTER OF HORICON...ON THE WEST LEG OF HORSESHOE ROAD...JUST 
SOUTH OF COUNTY TRUNK HIGHWAY S.  THIS TORNADO THEN MOVED EAST/SOUTHEAST AND 
REACHED THE VILLAGE OF IRON RIDGE AT ABOUT 614 PM.

THE TORNADO CONTINUED EAST/SOUTHEAST JUST NORTH OF CTH S UNTIL IT REACHED THE 
DODGE COUNTY LINE AT 625 PM ON CTH S...OR 4.5 MILES SOUTHEAST OF HERMAN CENTER.  
THE TORNADO DISSIPATED IN WEST CENTRAL WASHINGTON COUNTY AT 628 PM ON CTH S JUST 
EAST OF LEVEL ROAD...OR 2.4 MILES NORTHWEST OF ST. LAWRENCE.

THE NATIONAL WEATHER SERVICE ISSUED A TORNADO WATCH FOR MOST OF SOUTHERN 
WISCONSIN AT 143 PM.  A SEVERE THUNDERSTORM WARNING WAS WAS ISSUED FOR RESIDENTS 
OF DODGE COUNTY AT 534 PM.  A TORNADO WARNING WAS ISSUED FOR DODGE COUNTY AT 
547 PM...GIVING COUNTY RESIDENTS A LEAD TIME OF 19 MINUTES FOR THE INITIAL SPIN 
UP AND 27 MINUTES FOR IRON RIDGE.

A TORNADO WARNING WAS ISSUED FOR WASHINGTON COUNTY AT 616 PM...GIVING THAT 
COUNTY/S RESIDENTS A 9 MINUTE LEAD TIME.

EYEWITNESS REPORTS AND NWS DOPPLER RADAR IMAGES SUGGEST THAT THE IRON RIDGE 
TORNADO WAS RAIN-WRAPPED AND THE PARENT THUNDERSTORM HAD A LOW CLOUD BASE. THIS 
COMBINATION MADE IT DIFFICULT TO SPOT THE TORNADO DUE TO REDUCED VISIBILITIES. 

THE DAMAGE SURVEY WAS CONDUCTED BY TWO NWS METEOROLOGISTS IN CONJUNCTION WITH 
DODGE COUNTY EMERGENCY MANAGEMENT AND LAW ENFORCEMENT OFFICIALS ON JUNE 2ND. 

$$

KAPELA/EISE/HENTZ

Click on images to enlarge

Tornado Damage Tornado Damage Tornado Damage
Tornado Damage Tornado Damage Tornado Damage


A sincere thanks is extended to the spotters for their willingness to share their photographs.


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