EF0 tornado, Collinsville to Portersville, Alabama, April 12, 2020

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 12, 2020

Touchdown

10:22 PM CDT (03:22 UTC)

Lifted

10:28 PM CDT (03:28 UTC)

On the ground

6 minutes

Path length

3.6 miles (5.7 km)

Path width

110 yards (101 m)

Deaths

0

Injuries

0

County

DeKalb County

Touchdown point

34.274, -85.856

Lift-off point

34.299, -85.803

Record number

2004122122-01

14 damage points were recorded along this path by NWS BMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 115 mph.

• Lines down, dozens snapped.
• Corridor of nearly complete tree destruction. Just south of centerline.
• Small area of timber destruction
• Rootball approx 15 ft. in diameter

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

Heavy rainfall occurred across the entire NWS Huntsville County Warning area, as well as damage from thunderstorm winds and a few tornadoes. ||While heavy rainfall reports were spread out across the CWFA, the most significant flash flooding occurred in Fort Payne and surrounding areas in Northeast Alabama. ||Intense rainfall of 6-6.5 inches fell in DeKalb County along Big Wills Creek.||A new Flood of Record crest of 17.94 feet occurred, surpassing the old Flood of Record (14.36) by a whopping 3.5 feet! More than 50 roads were shut down, with extensive flooding that occurred on Hwy 35 leading up to the Hwy 35/I459 interchange.

A tornado uprooted several trees along and just east of North Valley Avenue. Large branches were snapped off trees as the tornado tracked east of CR 822 before destroying a small barn shed along CR 853.

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

3 minutes of warning. NWS HUN issued a tornado warning for this county at 03:19 UTC, 3 minutes before the tornado touched down, in force until 03:45 UTC.

The county was under a tornado watch, issued at 20:20 UTC and running to 04:38 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 Moderate Risk, with a 0.15 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 00:58 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), 75 km away, was scanning. The volume nearest the touchdown began at 03:24 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 2020 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

72 more were confirmed in the United States that day.

All 73 of them

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.