ON THIS DATE
What had been a hot, sunny day 10 years ago quickly took a stormy and deadly turn at the Indiana State Fairgrounds. Seven people died and dozens were injured when a wind gust from approaching storms toppled stage rigging onto fans waiting for the Sugarland concert to start.
It was a Saturday in August of 2011. The temperature in Indianapolis had reached 90-degrees that afternoon. While fairgoers were enjoying the annual festivities at the fairgrounds, a stormy setup was brewing to our northwest. A cold front moving through the region had triggered thunderstorm activity out ahead of it. These storms swept the state, bringing large hail and damaging winds to central Indiana.
A Severe Thunderstorm Watch had been issued for northern Indiana early in the day. At 6 PM, the watchbox had been extended south to cover almost all of Central Indiana, including Marion County.
Shortly before 9 O’clock that night, wind gusts as high as 77 mph were reported in Plainfield and 70 mph gusts were recorded at Speedway. Hail of 2” in diameter was reported in Benton county.
A severe thunderstorm warning was issued for all of Marion County at 8:39 PM as the line of storms began to bow out due to strong winds.
7 minutes later, the Indiana State Fair stage collapsed, killing 7 people attending the concert.
Included below is an image of the storm reports from the Storm Prediction Center that day. More details on the storm reports can be found here.
NEW WORDING TO WARNINGS
Starting this month the NWS will now issue “Destructive” and “Considerable” threat categories to Severe Thunderstorm Warnings. Criteria include baseball size hail and 80mph winds.
Here are the new criteria from the National Weather Service
- The criteria for a destructive damage threat is at least 2.75 inch diameter (baseball-sized) hail and/or 80 mph thunderstorm winds. Warnings with this tag will automatically activate a Wireless Emergency Alert (WEA) on smartphones within the warned area.
- The criteria for a considerable damage threat is at least 1.75 inch diameter (golf ball-sized) hail and/or 70 mph thunderstorm winds. This will not activate a WEA.
- The criteria for a baseline or “base” severe thunderstorm warning remains unchanged, 1.00 inch (quarter-sized) hail and/or 58 mph thunderstorm winds. This will not activate a WEA. When no damage threat tag is present, damage is expected to be at the base level.
On average only 10% of all severe t-storms reach the “destructive” category. This new tag will automatically activate a Wireless Emergency Alert (WEA) on smartphones within the warned area. Image below.