7 Year Anniversary Of Memorial Day Weekend 2004 Tornado Outbreak

Today marks the 7 year anniversary of what was then the second biggest tornado outbreak in state history (it has since been nudged into third place by 4/19/11).  The preceding days featured a series of severe weather events across the U.S., but on May 30, it was our turn to be in the crosshairs.

Early that day, the Storm Prediction Center issued a Moderate Risk roughly along and west of I-65 with a High Risk farther west in parts of Illinois.  The High Risk was expanded in subsequent outlooks to include most of Indiana:

The event began rather early with the first tornado reported in Owen county a few minutes after 1 PM.  It was the first of 24 tornadoes which occurred in a 9 hour time span.  2 of the tornadoes - Marengo and Peru - were rated F3 with 1 fatality in Marengo. 

Here is a map of the approximate tornado tracks:

Dubois County Tornado "Bonanza" One For The Record Books

With 2 confirmed tornadoes on Wednesday, Dubois county raised its 2011 total to 8 tornadoes.  If that seems like a lot, you are correct.  That is the most tornadoes in any Indiana county in one year since records have been kept.  What is perhaps more amazing is that it is more tornadoes than Dubois county had in the previous 40 years COMBINED!  Increased reporting and surveying with time likely plays a role but it seems that this has been a real hot spot this year.

Here is a list of Dubois county tornadoes from 1950-2010:

17 Tornadoes Now Confirmed In Indiana From May 25 Outbreak

Several additional tornadoes have been confirmed, bringing the event total to 17.  Here is the breakdown by area and intensity, subject to future modification.


NWS Indianapolis:  6
1 EF0, 4 EF1, 1 EF2

NWS Louisville:  5
3 EF1, 2 EF2

NWS Chicago:  4
1 EF0, 2 EF1, 1 EF2

NWS North Webster:  1
1 EF0

NWS Paducah:  1
1 EF2

Preliminary count of 50 tornadoes in 2011, breaking the all-time record of 49

So far there have been 50 tornadoes documented in the state this year, which breaks the previous record of 49 set in 1973 and 1990.  This number may rise as additional surveys of Wednesday's damage are done.

At Least 13 Tornadoes Confirmed From Wednesday's Severe Storms

National Weather Service teams have found at least 13 tornadoes from Wednesday's storms.  Surveys are still ongoing so it's possible if not probable that this number will rise.  Here is the breakdown:

6 NWS Indianapolis
4 NWS Chicago
2 NWS Louisville
1 NWS North Webster

NWS Confirms Tornado In Huntington County

The National Weather Service in North Webster has confirmed an EF0 tornado from Monday's storms.


PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE NORTHERN INDIANA
545 PM EDT TUE MAY 24 2011 /445 PM CDT TUE MAY 24 2011/ 
 
..EF0 TORNADO CONFIRMED IN HUNTINGTON COUNTY INDIANA


NATIONAL WEATHER SERVICE METEOROLOGISTS FROM NORTHERN INDIANA 
SURVEYED DAMAGE IN SOUTHWESTERN HUNTINGTON COUNTY INDIANA TODAY. THE 
SURVEY CONFIRMS THAT A WEAK EF0 TORNADO OCCURRED 3 MILES NORTH OF 
MT. ETNA. 

THE TORNADO FORMED IN A WOODED AREA WEST OF THE INTERSECTION OF 300 
SOUTH AND INDIANA HIGHWAY 9. THE TORNADO CROSSED OVER HIGHWAY 9 AND 
ENDED IN A STAND OF TREES EAST OF THE HIGHWAY. THE TORNADO REMAINED 
ON THE GROUND FOR APPROXIMATELY ONE-THIRD OF A MILE OR 650 YARDS. 

DAMAGE CONSISTENT WITH EF0 INTENSITY WINDS...ESTIMATED TO BE 65 
MPH...OCCURRED IN THE WOODED AREAS. THE MAXIMUM WIDTH OF THE TORNADO 
WAS 30 YARDS. 

TRAINED SPOTTER REPORTS AND OTHER EYEWITNESS REPORTS ARE CONSISTENT 
WITH THE DAMAGE OBSERVED IN THE AREA.   

NWS Confirms Tornado Just North Of Rensselaer

The National Weather Service in Chicago has confirmed that an EF1 tornado struck just north of Rensselaer in Jasper county on Sunday.  Here are the stats from the storm survey:


PATH LENGTH: 1/4 MILE
PATH WIDTH: 20-33 YARDS
LOCATION: 1 MILE NORTH OF RENSSELAER, IN
TIME: 4:37 PM (PRELIMINARY)

Pictures and a summary can be found here:

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=lot&storyid=68657&source=0

It appears that additional tornadoes occurred today, and more information will be posted as soon as it becomes available.

Last but not least, it appears that a rather significant severe weather threat is taking shape for Wednesday, including the possibility of tornadoes.  I will have more on this later.

May 18, 1927 Indianapolis Tornado

A powerful tornado moved through the heart of Indianapolis 84 years ago today.  This tornado took the lives of 2 people and injured up to 200 others.  Although he rated it F3, Tom Grazulis notes that this tornado may have been F4.

 
Source:

Thomas P. Grazulis, Significant Tornadoes 1680-1991 (Environmental Films, 1993).

Violent Tornadoes And Recent Trends

F4/F5 tornadoes generate some of the strongest winds on the face of the earth and produce extreme damage.  Since 1950, Indiana has had over 2 dozen violent tornadoes which have occurred on 13 days.  3 days (4/11/1965, 4/3/1974, 6/2/1990) are responsible for a majority of the violent twisters, and these are the only days since 1950 to have at least 2 violent tornadoes.

Approximate F4/F5 tornado tracks, 1950-2010

April is a hot month with 5 out of the 13 violent tornado days occurring then. The median occurrence for a violent tornado is day #115 or April 25. Indeed, 2 violent tornadoes happened on or near this date, those being 4/25/61 and 4/26/94. Also, over half of the dates (7 out of 13) fall within the 60 day window of April 3 to June 2.

While we are past the median date for violent tornadoes, it does not mean that we should let our guard down until next year.  Violent tornadoes can happen at any time of year if the proper conditions come together.  It has been 13 years since our last violent tornado, which is the longest period without one since 1950.  While nobody can predict the date or location of the next one, it is only a matter of time until another one occurs.

May Tornadoes Per County Since 1950