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| Earth on Aug 15, 2011

After Indiana State Fair tragedy, a call to heed weather warnings

Can we use this tragedy to learn from our mistakes?

The Indiana State Fair reopened in Indianapolis earlier today after strong thunderstorms producing 70 mile per hour (mph) winds sent lights and rigging crashing down on a concert stage two days ago (August 13, 2011). The tragedy at the Indiana State Fair killed five and injured over 40 people.

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It was a Saturday night – at around 8:50 p.m. Sugarland was about to perform, and thousands of people were ready to have fun. Most probably didn’t know that an approaching line of severe thunderstorms was pushing into the area.

First of all, I am deeply saddened to hear the news of this horrible event.  My prayers go out to all of the victims of this storm.  I got into meteorology to help save lives.  In Indianapolis that day, watches and warnings were issued well in advance of this line of storms, and the threat for strong winds was mentioned by weather forecasters early that morning. 

My question is:  When will we learn from our mistakes?

In terms of outdoor events and weather warnings, the disaster in Indiana was not an isolated event. I’ve seen instances when a tornado outbreak is forecast, but a baseball game is still set to throw the opening pitch in the middle of the possible threat. Why do we continue to do this, when the heeding of weather warnings can save lives?

I looked into the science of how the August 13 storms developed, and why they saw 60-70 mph windspeeds at the Indiana State fair.

That Saturday morning, the Storm Prediction Center (SPC) released their convective Day 1 outlook for the United States, shown in the image below.

SPC Day 1 Outlook for Indiana on August 15 2011

Indiana included in the slight risk for severe thunderstorms on August 15, 2011. Image Credit: Storm Prediction Center

SPC also outlined the biggest severe weather threats for the United States.  They included much of Illinois and Indiana in a 30 percent probability of seeing 50 knot (60 mph) winds or higher within 25 miles of a point:

Day 1 Wind outlook for Indiana on 8/13/2011

Day 1 Wind outlook for Indiana on 8/13/2011. Image Credit: Storm Prediction Center

As you can see in the images above, the SPC had already forecast the potential for severe weather in the Indianapolis area early Saturday morning.  Here’s a word-by-word discussion from the SPC that morning:

Low level destabilization and ascent ahead of both Minnesota/Iowa trough and the secondary impulse pivoting southeast across Missouri should lead to the development of scattered strong to severe thunderstorms along cold front from northern/central Illinois and perhaps far eastern Iowa east-northeast into northwest Indiana and lower Missouri by early to mid afternoon. With region in zone of ascent along and north of 40-45 knot westerly mid level jet streak …. Setup appears favorable for sustained storms/supercells/some of which may organize into bows with severe wind and hail. [Emphasis added by author]

With this is mind, let’s look at a radar image prior to the wind event:

Line of severe thunderstorms pushing southeast into Indianapolis. Image Credit: Nexrad Level 2 Radar image from Brad Panovich

As you can see in the radar image above, a well-established squall line was approaching the area.  In my opinion, it would have been a good time to cancel fair events immediately and let everyone seek shelter from the approaching storm.

When you look at that radar image, you assume the winds are associated with the squall line of storms.  However, if you look closely at a later image, you’ll see something else, as the image below shows:

Squall line approaching Indianapolis on 8. 13. 2011 with gust front

Radar showing strong winds ahead of the line of organized storms.

In the image above, you can see a blue line stretching out ahead of the main line of storms.  This is called a “gust front,” or an outflow boundary of winds that occur ahead of storm systems.  In most bow echos or squall lines, the damaging winds are typically those ahead of the system. Do you ever recall strong, cool winds before a thunderstorm?  This wind is outflow from the approaching storm. Outflow winds can be seen on radar (highlighted in the image above), but forecasting the windspeeds from the gust front can be tricky.  For this instance, the gust front that pushed into the fair around 8:50 p.m. left disaster in its wake.

The fair had contacted the National Weather Service in regard to the severe weather. Indications were that the storms were going to push through the area around 9:15 p.m. local time. Loudspeakers at the fair broadcast the threat of severe weather.  Still, tragedy struck.

My biggest concern is for the people who were injured or killed in this event and their families.

But I also want people to recognize and understand the term “severe thunderstorm warning.” 

When you hear there is a severe thunderstorm warning, do you listen? Do you take shelter when you hear this term for your county area?  Severe thunderstorm warnings are defined as producing at least 60 mph winds, quarter-sized hail or larger, and sometimes tornadoes. Plus – if you hear thunder – then you can be struck by lightning. 

Can we learn from our mistakes?

Squall lines, in my opinion, can be more dangerous than a tornado. They impact a larger area of territory and can produce damaging winds that can knock over trees and power lines. Just look at the spring of 2011, when we saw this sort of damage happening everywhere across the southeast. Awareness – on the part of organizers of public outdoor events, those who attend them, and all people everywhere – is key.

The evening of August 13, 2011 will remain in our memories. All prayers go out to the victims of the tragedy at the 2011 Indiana State Fair and their families. I hope those that are injured can make a fast recovery. Who could forget a time when 70 mph winds brought down a concert stage and killed at least five people?  I hope we can learn from our mistakes so we can prevent a tragedy such as this from happening in our future. 

Will we learn?