...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
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.
Click on images to enlarge