Tornadoes · United States · Alabama · 1977

F3 tornado, DeKalb County, Alabama, March 30, 1977

This F3 tornado ran 9.2 miles across DeKalb County on March 30, 1977, touching down at 8:15 AM CST and reaching 50 yards wide. It killed nobody and injured 2, and did $50,000 to $500,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 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. F3158 to 206 mphthis tornado

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 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.

The record

Rating
F3
Date
March 30, 1977
Touchdown
8:15 AM CST (14:15 UTC)
Path length
9.2 miles (14.8 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
2
Property damage
$50,000 to $500,000
County
DeKalb County
Touchdown point
34.330, -86.070
Lift-off point
34.380, -85.920
Record number
80

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.

Centreville/Bibb, AL (KCKL), 12:00Z

2.3 hours before the tornado, 197 km from the path. March 30, 1977.

Skew-T log-pSkew-T log-p diagram, Centreville/Bibb, AL at 12:00Z on 1977-03-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 830 joules per kilogram, CIN -14, lifted condensation level 666 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Centreville/Bibb, AL at 12:00Z on 1977-03-30The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 191 square meters per square second, 0 to 6 km bulk shear 49 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
830 J/kg
Mixed-layer CIN
-14 J/kg
Surface CAPE
748 J/kg
Mixed-layer LCL
666 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
191 m²/s²
0-3 km storm-relative helicity
219 m²/s²
Significant tornado parameter
0.9
Supercell composite
4.3
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Centreville/Bibb, AL (KCKL), 00:00Z

9.7 hours after it, 197 km from the path. March 31, 1977.

Skew-T log-pSkew-T log-p diagram, Centreville/Bibb, AL at 00:00Z on 1977-03-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2047 joules per kilogram, CIN -1, lifted condensation level 703 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Centreville/Bibb, AL at 00:00Z on 1977-03-31The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 83 square meters per square second, 0 to 6 km bulk shear 38 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
2047 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
2585 J/kg
Mixed-layer LCL
703 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
1.2
Supercell composite
6.4
0-3 km lapse rate
6.4 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1977 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

The other tornadoes of March 30, 1977

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 308:35 AM CSTF2DeKalb, AL2.5501$5,000 to $50,000
March 3011:00 AM ESTF2Gordon, GA11.0400$50,000 to $500,000
March 3011:30 AM ESTF2Gilmer, GA2.01004$50,000 to $500,000
March 305:30 PM ESTF1Oceana, MI1.5403$5,000 to $50,000
March 306:02 PM ESTF1Geauga, OH0.550$5,000 to $50,000
March 308:10 PM ESTF1Westmoreland, PA1.0400

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.