EF1 tornado, Spurgeon, Indiana, April 26, 2011

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 mphthis tornado

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

3. EF2111 to 135 mph

   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

EF1

Date

April 26, 2011

Touchdown

3:09 AM EDT (07:09 UTC)

Lifted

3:10 AM EDT (07:10 UTC)

On the ground

1 minutes

Path length

0.5 miles (0.9 km)

Path width

225 yards (206 m)

Deaths

0

Injuries

0

Property damage

$110,000

County

Pike County

Touchdown point

38.247, -87.261

Lift-off point

38.252, -87.254

Record number

1104260109-01

A pronounced mid-level shortwave trough and associated 70 to 80 knot mid-level jet progressed northeastward from the southern Plains across Arkansas and Missouri. An associated surface low developed northeastward from southwest Missouri toward northwest Illinois. A gradual increase in the warm sector southerly low level jet occurred as the surface low deepened. Increasing vertical wind shear in the moist and unstable warm sector resulted in organized severe storms. The storms were organized into bowing lines with embedded supercell structures.

The tornado began on Indiana Route 61 just south of Spurgeon. It travelled northeast across the eastern outskirts of Spurgeon. Numerous trees were snapped at the base. Several trees were uprooted. Several homes received minor roof damage. A barn was damaged, with debris carried a couple hundred yards. A small building was destroyed. Severe straight-line winds caused other damage throughout the town of Spurgeon. Peak winds were estimated near 105 mph. The average path width was 200 yards.

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

2 minutes of warning. NWS PAH issued a tornado warning for this county at 07:07 UTC, 2 minutes before the tornado touched down, in force until 07:19 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 06:09 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 Evansville,IN radar (KVWX), 41 km away, was scanning. The volume nearest the touchdown began at 07:07 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 2011 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

58 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.