EF2 tornado, Chesterton to Tremont, Indiana, August 19, 2009

1. EF065 to 85 mph

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mphthis tornado

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF2

Date

August 19, 2009

Touchdown

7:32 PM CDT (00:32 UTC)

Lifted

7:45 PM CDT (00:45 UTC)

On the ground

13 minutes

Path length

4.0 miles (6.4 km)

Path width

60 yards (55 m)

Deaths

0

Injuries

0

Property damage

$1.5 million

County

Porter County

Touchdown point

41.604, -87.065

Lift-off point

41.656, -87.032

Record number

0908191832-01

Strong to severe thunderstorms moved across parts of northwest Indiana during the late afternoon and evening hours of August 19th, producing one tornado in Chesterton.

A tornado touched down in southern Chesterton east of 11th Street and southwest of South Park Drive. The tornado quickly intensified as it moved to the northeast and caused the partial collapse of a gymnasium roof at the Chesterton Junior High School. A wind gust to 105 mph was measured by an anemometer near the school. This damage along with numerous trees that were either uprooted or sheared off was caused by tornado winds reaching 110 mph. The tornado was rated EF1 at this point with a path width of 40 yards. The tornado continued to track to the northeast across the New York Central railroad tracks toward Grant Avenue where the roof of a warehouse had been peeled off and thrown about 15 yards behind the building to the north. The tornado continued to the northeast where an apartment building on Brown Avenue lost its entire roof. This damage was caused by tornado winds reaching 120 mph. The tornado damage was rated EF2 through this area with a path width of 60 yards. In the city of Chesterton, 211 structures sustained damage; 8 were completely destroyed; 54 suffered major damage, such as trees falling through roofs. The remaining 149 structures sustained damage such as missing shingles or damaged gutters. Multiple vehicles were damaged by falling debris from buildings or trees. Numerous power lines were blown down along with utility poles blown down or snapped. This EF2 damage continued northeast where an entire field of healthy old hardwood tree trunks were snapped off or uprooted. The tornado then started to slightly weaken as it approached the Interstate 94 eastbound exit/westbound entrance ramps at Indiana Highway 49. A home south of the interstate had a garage roof blown off with still numerous trees uprooted or sheared off. Tornado wind speeds here were estimated at 100 mph with an EF1 rating. Similar tree damage was noted along a path that continued to go to the northeast across Highway 49 and toward Highway 20 near Hadenfelt Road where some aluminum roofing material of a storage facility had been peeled off. Tornado wind speeds were estimated at 95 mph here and was rated EF1 with a path width of 30 yards. The tornado continued to move through a heavily forested area in the Indiana Dunes National Lakeshore, eventually crossing Highway 12. Radar imagery and an aerial survey suggests that the tornado dissipated north of Highway 12.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

2 minutes of warning. NWS LOT issued a tornado warning for this county at 00:30 UTC, 2 minutes before the tornado touched down, in force until 00:49 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a General Thunderstorms Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 21:34 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

The Chicago radar (KLOT), 86 km away, was scanning. The volume nearest the touchdown began at 00:31 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2009 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

29 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.