EF1 tornado, Mc Nair to Harriston, Mississippi, March 21, 2012

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

March 21, 2012

Touchdown

10:23 AM CDT (15:23 UTC)

Lifted

10:29 AM CDT (15:29 UTC)

On the ground

6 minutes

Path length

2.7 miles (4.4 km)

Path width

176 yards (161 m)

Deaths

0

Injuries

0

Property damage

$20,000

County

Jefferson County

Touchdown point

31.638, -91.026

Lift-off point

31.674, -91.007

Record number

1203210923-01

A slow moving storm system combined with abundant moisture to bring nearly 48 hours of rain and thunderstorms to the ArkLaMiss region, beginning on the evening of March 20th and continuing through the afternoon hours of March 22nd. Strong winds in the atmosphere interacted with a cold front to bring severe thunderstorms, tornadoes and widespread flooding to the region. The primary impacts from this system were tornadoes and flooding, but there were also many reports of damaging winds. With rich moisture flowing north from the Gulf of Mexico, many of the storms were efficient rain makers that ended up producing both flash flooding and river flooding. Most areas west of the I-55 corridor received one to three inches, areas along the I-55 corridor received between three and four inches, and up to eight inches was observed east of I-55.

The tornado snapped numerous pine trees and uprooted oak trees over a rural part of the county. Maximum wind speed was estimated at 94 mph.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

The county was under a tornado watch, issued at 15:10 UTC and running to 16:59 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 12:28 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.

Natchez/Hardy(Awos) (HEZ), 27 km from the path, in the two hours either side.

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

The Jackson/Brandon,MS radar (KDGX), 120 km away, was scanning. The volume nearest the touchdown began at 15:21 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 2012 tornado in MississippiEvery tornado in Mississippi since 1950Warnings in force in Mississippi nowThe forecast where you are

20 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.