EF1 tornado, Norphlet, Arkansas, April 4, 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 4, 2011

Touchdown

10:12 AM CDT (15:12 UTC)

Lifted

10:13 AM CDT (15:13 UTC)

On the ground

1 minutes

Path length

1.3 miles (2.1 km)

Path width

100 yards (91 m)

Deaths

0

Injuries

0

Property damage

$150,000

County

Union County

Touchdown point

33.318, -92.665

Lift-off point

33.320, -92.643

Record number

1104040912-01

10 damage points were recorded along this path by NWS SHV, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 95 mph.

• large tree snapped near a home in norphlet
• small limbs broken in and around a home on hayes street
• carport collapsed on a car
• large tree uprooted on mayors house

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

A strong upper level short wave move from west to east across the Central Plains states of the U.S. driving a cold front southeast into the Four State Region. Strong to severe thunderstorms formed in the unstable air mass ahead of the cold front. The front and at least 3 lines of thunderstorms moved through the Four State Region from west to east during the day. Strong low level shear in the atmosphere allowed some thunderstorms to rotate, producing tornadoes with damaging straight line winds producing downbursts.

The National Weather Service conducted a storm survey in Union County Arkansas and concluded that storm damage was the result of an EF1 tornado. The tornado touched down at around 10:12 AM, in the town of Norphlet. An old gas station cover was blown down and several trees were snapped along Black street eastward across Hayes St. Some minor roof damage occurred to homes along Hayes street. The tornado continued eastward crossing N Tate Road where a carport collapsed on a vehicle and several trees were snapped or uprooted. The tornado continued along the south side of Tate Road snapping trees and peeling shingles from several homes. The tornado lifted east of a pasture where several hardwood and softwood trees were snapped or uprooted. A small metal outbuilding suffered structural damage as well. Maximum winds are estimated at 90-100 mph.

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

42 minutes of warning. NWS SHV issued a tornado warning for this county at 14:30 UTC, 42 minutes before the tornado touched down, in force until 15:15 UTC.

The county was under a severe thunderstorm watch, issued at 12:50 UTC and running to 19:48 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 13:11 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 Shreveport radar (KSHV), 147 km away, was scanning. The volume nearest the touchdown began at 15:10 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 ArkansasEvery tornado in Arkansas since 1950Warnings in force in Arkansas nowThe forecast where you are

42 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.