EF1 tornado, Allen, Alabama, March 31, 2021

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 31, 2021

Touchdown

5:44 AM CDT (10:44 UTC)

Lifted

5:52 AM CDT (10:52 UTC)

On the ground

8 minutes

Path length

3.2 miles (5.1 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

County

DeKalb County

Touchdown point

34.525, -85.728

Lift-off point

34.524, -85.673

Record number

2103310444-01

11 damage points were recorded along this path by NWS HUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 86 mph.

• Chicken houses with part of roof removed
• Well anchored porch removed

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

Two thunderstorm complexes moved through north Alabama during the early and mid morning hours of the 31st. Rainfall of 1 to nearly 3 inches were reported during this time, resulting in flash flooding of a few roads in Jackson County. In addition, a couple of brief tornadoes occurred. One tornado moved out of Winston County and lifted just inside western Cullman County producing EF-0 damage. An EF-1 tornado track was observed in DeKalb County between Fort Payne and Valley Head.

A tornado touched down just east of County Road 486 near County Road 603 where a few large limbs were broken and a house suffered minor roof damage. From there, the tornado traveled eastward where a row of chicken houses had part of their roofs removed. In this location, along County Road 698, a well anchored porch was removed from a manufactured home. The tornado continued on its eastward path toward County Road 952 where the most extensive damage occurred. Here, dozens of trees were snapped or uprooted, and one home sustained minor damage. The tornado lifted just east of 68th Street Northwest.

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.

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 Marginal Risk. The outlook in force was issued at 05:45 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 Northeast Alabama radar (KHTX), 57 km away, was scanning. The volume nearest the touchdown began at 10:43 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 2021 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

4 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.