Tornadoes · United States · Alabama · 2021
EF0 tornado, Hamilton Arpt to Hamilton, Alabama, March 31, 2021
From Hamilton Arpt to Hamilton, this EF0 tornado ran 1.6 miles across Marion County on March 31, 2021, touching down at 2:31 AM CDT and reaching 90 yards wide. It killed nobody.
The rating scale
Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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.
The record
- Rating
- EF0
- Date
- March 31, 2021
- Touchdown
- 2:31 AM CDT (07:31 UTC)
- Lifted
- 2:34 AM CDT (07:34 UTC)
- On the ground
- 3 minutes
- Path length
- 1.6 miles (2.6 km)
- Path width
- 90 yards (82 m)
- Deaths
- 0
- Injuries
- 0
- County
- Marion County
- Touchdown point
- 34.061, -87.996
- Lift-off point
- 34.076, -87.974
- Record number
- 2103310131-01
The damage survey
6 damage points were recorded along this path by NWS BMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 75 mph.
- Suspected start point per TDS on KMXX RADAR.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
A warm front moved pushed northward into north Central Alabama late on March 30th and into the early morning hours on March 31st. A low pressure area developed along the warm front and tracked from west to east across northern Alabama. This feature pooled instability just south of the front and added just enough shear for some rotating and organized storms. Subsequently, three weak and short-lived tornadoes developed. Due to the strong southerly winds and lift near the front, heavy rainfall was observed across northern Alabama. Widespread amounts of 1 to 3 inches of rain were observed with localized amounts of 5 to 6 inches west of I-65. These amounts produced flash flooding in several locations where roads were washed out and or became impassable. Additionally, many local creeks and streams flooded and this eventually lead to river and lake flooding.
National Weather Service meteorologists surveyed damage in southern Marion County and determined that it was consistent with an EF0 tornado, with maximum winds near 80 mph. ||The tornado began in a wooded area just north of Stakehouse Road where several large branches were broken. The tornado then traveled northeast where it crossed I-22 and the intersection of Berryhill Road and Highway 278. In this area, several softwood trees were uprooted and additional large branches were broken. The tornado continued northeast into a deforested area and lifted.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
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.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 00:00 UTC | 22:40 UTC | Flash Flood Watch | BMX |
| 07:10 UTC | 07:25 UTC | Tornado Warning | BMX |
| 09:38 UTC | 13:45 UTC | Flash Flood Warning | BMX |
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 forecast that day
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 air that afternoon
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.
Birmingham, AL (KBMX), 00:00Z
7.5 hours before the tornado, 149 km from the path. March 31, 2021.
- Mixed-layer CAPE
- 127 J/kg
- Mixed-layer CIN
- -12 J/kg
- Surface CAPE
- 273 J/kg
- Mixed-layer LCL
- 1179 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- 74 m²/s²
- 0-3 km storm-relative helicity
- 179 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
- 0-3 km lapse rate
- 7.2 K/km
Birmingham, AL (KBMX), 12:00Z
4.5 hours after it, 149 km from the path. March 31, 2021.
- Mixed-layer CAPE
- 455 J/kg
- Mixed-layer CIN
- -3 J/kg
- Surface CAPE
- 622 J/kg
- Mixed-layer LCL
- 527 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 273 m²/s²
- 0-3 km storm-relative helicity
- 283 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.5
- 0-3 km lapse rate
- 5.9 K/km
The surface observations
Haleyville (1M4), 43 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 05:35 UTC | 190° 10 kt | 1017.3 | -RA | |||
| 05:40 UTC | 200° 11 kt | 1017.3 | -RA | |||
| 05:45 UTC | 200° 11 kt | 1016.9 | -RA | |||
| 05:50 UTC | 180° 11 kt | 1016.9 | -RA | |||
| 05:55 UTC | 200° 13 kt | 1017.3 | -RA | |||
| 05:56 UTC | 67 | 66 | 200° 13 kt | 19 | 1016.9 | RA |
| 06:00 UTC | 14 kt | 1016.9 | -RA | |||
| 06:05 UTC | 200° 14 kt | 1016.9 | -RA | |||
| 06:10 UTC | 11 kt | 1016.9 | -RA | |||
| 06:15 UTC | 200° 11 kt | 1016.9 | -RA | |||
| 06:20 UTC | 200° 14 kt | 1016.6 | -RA | |||
| 06:25 UTC | 200° 14 kt | 1016.9 | -RA | |||
| 06:30 UTC | 14 kt | 1016.9 | RA | |||
| 06:35 UTC | 190° 10 kt | 1016.6 | RA | |||
| 06:40 UTC | 11 kt | 1016.9 | RA | |||
| 06:45 UTC | 190° 10 kt | 1016.6 | RA | |||
| 06:50 UTC | 200° 10 kt | 1016.6 | RA | |||
| 06:55 UTC | 11 kt | 1016.6 | RA | |||
| 06:56 UTC | 67 | 66 | 200° 11 kt | 20 | 1016.6 | VCTS RA |
| 07:00 UTC | 210° 10 kt | 1016.9 | RA | |||
| 07:05 UTC | 11 kt | 1016.9 | RA | |||
| 07:10 UTC | 11 kt | 16 | 1016.3 | +RA BR | ||
| 07:15 UTC | 200° 8 kt | 1016.6 | RA BR | |||
| 07:20 UTC | 11 kt | 1016.6 | RA | |||
| 07:25 UTC | 210° 11 kt | 1016.9 | RA | |||
| 07:30 UTC | 220° 15 kt | 1016.9 | RA | |||
| 07:35 UTC | 210° 9 kt | 1016.6 | +RA BR | |||
| 07:40 UTC | 220° 10 kt | 1016.6 | +RA BR | |||
| 07:45 UTC | 240° 7 kt | 1016.6 | +RA BR | |||
| 07:50 UTC | 230° 5 kt | 1016.3 | +RA | |||
| 07:52 UTC | 64.4 | 62.6 | 4 kt | 1016.3 | TSRA | |
| 07:55 UTC | 0° 0 kt | 1015.9 | RA | |||
| 07:56 UTC | 64 | 63 | 0° 0 kt | 1015.9 | TSRA | |
| 08:00 UTC | 350° 5 kt | 1015.6 | +RA | |||
| 08:05 UTC | 330° 5 kt | 1015.6 | +RA BR | |||
| 08:10 UTC | 250° 8 kt | 1016.9 | +RA BR | |||
| 08:11 UTC | 64.4 | 62.6 | 250° 8 kt | 1016.9 | +RA BR | |
| 08:15 UTC | 310° 2 kt | 1016.3 | +RA BR | |||
| 08:20 UTC | 270° 4 kt | 1016.6 | +RA BR | |||
| 08:25 UTC | 240° 4 kt | 1016.3 | RA BR | |||
| 08:30 UTC | 250° 5 kt | 1016.6 | RA | |||
| 08:35 UTC | 250° 4 kt | 1016.3 | RA | |||
| 08:38 UTC | 62.6 | 62.6 | 230° 3 kt | 1016.3 | RA | |
| 08:40 UTC | 240° 2 kt | 1016.3 | RA | |||
| 08:45 UTC | 220° 5 kt | 1016.6 | RA | |||
| 08:50 UTC | 230° 5 kt | 1016.6 | RA | |||
| 08:55 UTC | 220° 5 kt | 1016.6 | -RA | |||
| 08:56 UTC | 63 | 62 | 210° 6 kt | 1016.3 | -RA | |
| 09:00 UTC | 210° 5 kt | 1016.6 | -RA | |||
| 09:05 UTC | 220° 7 kt | 1016.6 | -RA | |||
| 09:10 UTC | 230° 7 kt | 1016.6 | RA | |||
| 09:15 UTC | 210° 7 kt | 1016.3 | RA | |||
| 09:20 UTC | 220° 8 kt | 1016.6 | -RA | |||
| 09:25 UTC | 210° 8 kt | 1016.6 | RA | |||
| 09:26 UTC | 62.6 | 62.6 | 210° 8 kt | 1016.9 | RA | |
| 09:30 UTC | 240° 8 kt | 1017.6 | RA |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Columbus AFB radar (KGWX), 37 km away, was scanning. The volume nearest the touchdown began at 07:30 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.
What was reported nearby
Local storm reports within 60 km of the path, in the three hours either side.
| Time (UTC) | Report | Where | County | Remark |
|---|---|---|---|---|
| 07:31 UTC | TORNADO | 1 Nw Marion County Publ | Marion, AL | AN EF-0 TORNADO TOUCHED DOWN SOUTH OF HAYDEN WITH THE MAJORITY OF THE DAMAGE CONSISTING OF DOWNED TREES. THE TORNADO WAS ON THE GROUND FOR 1.63 MILES. THE MAX WIDTH WAS 90 YARDS AND MAX WINDS WERE 80S MPH. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2021 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are
The other tornadoes of March 31, 2021
4 more were confirmed in the United States that day.
What this means
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.
Sources
NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.