15 Tornadoes on April 10th...Biggest Daily April Tornado Outbreak Ever in Wisconsin (updated noon May 18th)

       Updated - noon CDT Wednesday May 21, 2011

         What's new - a weak tornado documented in Green Lake County

Although the major metro areas like Madison, Milwaukee, and Chicago were spared, at least 15 tornadoes, including four strong tornadoes (EF2 or EF3), were documented in portions of mainly rural central and northern Wisconsin.  The potential for a tornado outbreak in the Wisconsin area was advertised almost a week out with the models showing favorable conditions ripe for the tornado outbreak.  

April 10 2011 will go down as the biggest daily April tornado outbreak (in terms of total tornadoes) in Wisconsin history.  The other big April tornado outbreak was on April 27 1984, when 10 tornadoes occurred, of which 6 were considered at least strong.  This included the violent Wales Tornado in Waukesha County, rated an F4, and another F4 tornado in Winnebago and Outagamie Counties.

The EF3 tornado on April 10, 2011 occurred near Merrill in Lincoln County. EF2 tornadoes were also documented in Adams County, Forest County, and Brown County (see table and graphic below for locations). 

These are the first strong tornadoes in 17 years for the month of April in Wisconsin (the last being April 26 1994 in NW Wisconsin).  They are also the first strong tornadoes in 27 years in the month of April for central or southern WI (April 27 1984). 

Damage assessment continues, which means more tornadoes may be found and recorded in the next few days.  Below is a rough plot of the tornado locations and EF-rating.

 Below is a listing of the April 10th tornadoes in Wisconsin...subject to change as new information becomes available.

 

Time
(PM CDT)
County
Start
End
EF
Path
Length
Path
Width
Max Wind
457-503
Eau Claire
5SW Augusta
3.5SW Augusta
EF1
1.5 miles
unknown
105 mph
504-506
Eau Claire
1.3 NW Augusta
2NNW Augusta
EF1
¾ mile
unknown
100 mph
608-641
Lincoln
2N Hamburg
Near Gleason
EF3
21.2 miles
1050 yds
140 mph
612-630
Adams
3W Arkdale
5.5NW Coloma
EF2
17 miles
800 yds
125 mph
614-621
Juneau
2.4 SSW Necadah
3.5 ESE Necadah
EF1
4.5 miles
150 yds
95 mph
633–642
Adams – Waushara
6SW Hancock
2SE Hancock
EF1
9.3 miles
140 yds
100 mph
650-658
Langlade
S of Parrish
E of Parrish
EF1
5.3 miles
400 yds
110 mph
706-743
Waushara-Waupaca –
Outagamie
Saxeville
Hortonville
EF1
27.7 miles
200 yds
100 mph
730-751
Forest –
Florence
3 SE Argonne
6 SE Long Lake
EF2
12 miles
600 yds
115 mph
753-807
Waushara- Winnebago
Poy Sippi
2W Windchester
EF1
14.9 miles
150 yds
105 mph
803-808
Forest
4W Armstrong Creek
1NW Armstrong Creek
EF1
3.3 miles
250 yds
105 mph
827-829
Green Lake
3.5 SSE Berlin
3.4 SE Berlin
EF0
2.0 miles
50 yds
80 mph
843-846
Outagamie
Kaukauna (sw)
Kaukauna (s)
EF2
1.5 miles
175 yds
120 mph
853-855
Brown
1 S Greenleaf
1 S Greenleaf
EF1
1.2 miles
75 yds
95 mph
859-901
Calumet
1 S Stockbridge
1 S Stockbridge
EF1
1.7 miles
100 yds
90 mph
 


Below is a rough plot of the tornado locations and EF-rating (click on image for larger version)

Apr 10 2011 WI Tor Plot
 


APRIL 10 2011 SO FAR IS ONE OF THE BIGGEST DAILY TORNADO OUTBREAKS IN WISCONSIN HISTORY...NOW IN 6TH PLACE.

APRIL 10 2011, IS THE BIGGEST TORNADO OUTBREAK IN TERMS OF NUMBERS OF TORNADOES IN ONE CALENDAR DAY IN THE MONTH OF APRIL.   THE PREVIOUS RECORD WAS APRIL 27, 1984 WHICH HAD 10 TORNADOES. AT THE BOTTOM OF THIS STORY IS A PLOT OF THE TORNADO PATHS FOR APRIL 27, 1984.  TWO F4 TORNADOES OCCURRED ON APRIL 27, 1984 - ONE NEAR WALES AND THE OTHER IN WINNEBAGO AND OUTAGAMIE COUNTIES.  THE TORNADOES IN THAT OUTBREAK WERE STRONGER OVERALL...WITH 6 STRONG AND VIOLENT TORNADOES (F2 OR GREATER).  THIS COMPARES WITH 4 STRONG TORNADOES ON APRIL 10, 2011 (EF2 OR GREATER).

SO FAR...AT LEAST 15 TORNADOES HAVE BEEN CONFIRMED ON APRIL 10, 2011...WITH FOUR NWS OFFICES COMPLETING STORM SURVEYS.

HERE ARE THE TORNADO TOTALS* SO FAR:

NWS GREEN BAY AREA:       10                         NWS LA CROSSE AREA:        3               
NWS TWIN CITIES AREA:        2                          NWS MILWAUKEE AREA        1

THE TOTAL SO FAR IS 15* TORNADOES.  ONE OF THE TORNADOES CROSSED FROM ADAMS INTO WAUSHARA COUNTY...WHICH CROSSES FROM NWS LA CROSSE'S AREA INTO GREEN BAY'S AREA  (THUS ONLY 15 TORNADOES...NOT 16 AS THE MATH ABOVE WOULD SUGGEST).


Additionally, there were numerous reports of large hail and damaging thunderstorm winds across many parts of the state.  Hail stones up to 2.75 inches in diameter occurred and straight-line wind gusts up to 80 mph (hurricane-force) were noted by severe weather spotters.

A warm front pushed north into northern Wisconsin on Sunday, April 10th, which allowed temperatures to reach the 70s to lower 80s.  During the afternoon and evening hours a cold front punched east into this warm, humid, unstable airmass. Strong winds and the jet stream resulted in many supercell thunderstorms, some of which produced tornadoes. 

The storms started to rapidly develop around 4 p.m. and storm movement was very fast – 60 to 70 mph at times.  Moving at these speeds, the storms exited Wisconsin by 11 pm.


Related stories, greater detail, damage pictures, radar imagery, and tornado plot maps, can be found at these URLs...

http://www.crh.noaa.gov/grb/?n=110410_tornadoes

http://www.crh.noaa.gov/arx/?n=apr1011

http://www.crh.noaa.gov/mpx/?n=11apr10

http://emergencymanagement.wi.gov/


 HOW MANY TORNADOES HAVE OCCURRED IN WISCONSIN ON ONE DAY?


WISCONSIN NORMALLY DOESN'T HAVE MANY TORNADOES OCCURRING ON THE SAME DAY...CONSIDERING IT AVERAGES ONLY 21 TORNADOES PER YEAR (BASED ON 1971-2000).  HOWEVER...WHEN A TORNADIC WEATHER PATTERN DOES SET UP OVER WISCONSIN...THE BADGER STATE CAN HAVE MANY TORNADOES OCCURRING ON THE SAME DAY.

THE TABLE BELOW LISTS THOSE DAYS IN WISCONSIN WITH THE LARGEST NUMBER OF DOCUMENTED TORNADOES GOING BACK TO 1844. THE 15 TORNADOES DOCUMENTED ON APRIL 10, 2011 PLACES THAT DAY IN 6TH POSITION IN THE TOP-10 RANKINGS.

     ...RANK...      ...DATE...      ...NUMBER OF EVENTS...

         01          AUG 18 2005               27

         02          MAY 08 1988               24

         03          JULY 03 1983              22

         04          JUNE 08 1993              18

         05          JUNE 23 2004              17

         06          APRIL 10 2011             15

         07          JUNE 07 2008              13

         07          AUGUST 09 1979         13

         09          JULY 18 1996               12

         10          MAY 24 1989               10

         10          APRIL 27 1984             10

         10          JULY 15 1980               10

         10          JUNE 26 1969              10

         10          JULY 10 1966               10

         10          JUNE 04 2005              10

         10          JULY 22 2010               10

 


HOW MANY TORNADOES IN ONE DAY ACROSS SOUTH-CENTRAL AND SOUTHEAST WISCONSIN?

THE NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN FORECAST OFFICE SERVICES 20 COUNTIES IN SOUTH-CENTRAL AND SOUTHEAST WISCONSIN. THIS COUNTY WARNING AREA /CWA/ CONSISTS OF THE FOLLOWING COUNTIES...

COLUMBIA...DANE...DODGE...FOND DU LAC...GREEN...
GREEN LAKE...IOWA...JEFFERSON...KENOSHA...LAFAYETTE... MARQUETTE...MILWAUKEE...OZAUKEE...RACINE...ROCK...SAUK...SHEBOYGAN...WALWORTH...WASHINGTON...AND WAUKESHA...

BELOW IS THE TOP-10 RANKING FOR THOSE DAYS WITH THE LARGEST NUMBER OF DOCUMENTED TORNADOES ON A GIVEN CALENDAR DAY IN THE MILWAUKEE/SULLIVAN CWA.

     ...RANK...      ...DATE...      ...NUMBER OF EVENTS...

         01          AUGUST 18 2005         16

         02          MAY 08 1988               10

         02          AUGUST 09 1979         10

         02          JULY 18 1996               10

         02          JUNE 07 2008              10

         02          JULY 22 2010               10

         07          JUNE 08 1993               08

         07          JUNE 23 2004               08

         09          JUNE 08 1984               07

         09          JUNE 12 2008               07


Below is a graphic produced by Dan Baumgardt, SOO, WFO La Crosse, showing the tornado locations for the day of April 27, 1984.  Note that several of the tornadoes occurred in the same counties that had tornadoes on April 10, 2011.

  Apr 1984 tor map

CRAVEN/KAPELA/ZABEL/GEHRING



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