EF0 tornado, Clay to Calhoun, Louisiana, April 26, 2011

1. EF065 to 85 mphthis tornado

   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 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

EF0

Date

April 26, 2011

Touchdown

9:50 PM CDT (02:50 UTC)

Lifted

9:56 PM CDT (02:56 UTC)

On the ground

6 minutes

Path length

5.2 miles (8.4 km)

Path width

70 yards (64 m)

Deaths

0

Injuries

0

Counties

Jackson and Ouachita parishes

Touchdown point

32.467, -92.430

Lift-off point

32.515, -92.362

Record number

1104262050-01

36 damage points were recorded along this path by NWS SHV, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 85 mph.

• .SEVERAL BRANCHES AND LIMBS DOWN.
• NUMEROUS LARGE BRANCHES DOWN.
• .LARGE TREE FELL ON HOUSE,
• .VERY LARGE TREE UPROOTED.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

A very volatile atmosphere developed during the late afternoon...evening and overnight hours of April 26th across the Four State Region. An area of low pressure moved from the Texas Hill Country into Northeast Texas during the afternoon. Meanwhile, a warm front had moved northward from central Louisiana and was oriented west to east near the Arkansas/Louisiana state line. A dry line had moved just east of the I-35 corridor of North Central Texas and a strong cold front trailed the dry line. Very strong speed and directional shear was noted in the low and mid levels of the atmosphere such that supercells developed. Many of these produced tornadoes across the region. Other storms produced strong straight line wind gusts with bowing segments and large hail.

A few trees were blown over along Highway 818 between Clay, LA, and Woodville, LA, in far northern Jackson Parish with the initial touchdown of the tornado. The tornado then continued into southern Lincoln Parish. Maximum winds were estimated at 70-75 mph.

Several trees and power lines were blown over just west of the intersection of Highways 556 and 144 in northeastern Jackson Parish by the initial touchdown of the tornado. The tornado continued northeastward along Highway 144 in western Ouachita Parish.|Maximum winds were estimated at 80-85 mph.

This tornado is a continuation of the tornado that first touched down in northeast Jackson Parish. The tornado continued northeastward along Highway 144 in western Ouachita Parish snapping several very large trees just northeast of the Indian Village community. The tornado continued to knock over trees, ripping the tops off of trees, and breaking large branches out of trees along Highway 144 until it dissipated just west of the city of Calhoun just north of Highway 80. Maximum winds were estimated at 80-85 mph.

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

25 minutes of warning. NWS SHV issued a tornado warning for this county at 02:25 UTC, 25 minutes before the tornado touched down, in force until 03:00 UTC.

The county was under a tornado watch, issued at 02:41 UTC and running to 09:53 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 High Risk, with a 0.30 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:53 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.

Ruston (RSN), 18 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Shreveport radar (KSHV), 136 km away, was scanning. The volume nearest the touchdown began at 02:50 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 LouisianaEvery tornado in Louisiana since 1950Warnings in force in Louisiana 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.