Tornadoes · United States · Alabama · 2015

EF1 tornado, Sulphur Spgs, Alabama, April 3, 2015

This EF1 tornado ran 2.3 miles across DeKalb County on April 3, 2015, touching down at 9:05 PM CDT and reaching 75 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.

  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.

The record

Rating
EF1
Date
April 3, 2015
Touchdown
9:05 PM CDT (02:05 UTC)
Lifted
9:08 PM CDT (02:08 UTC)
On the ground
3 minutes
Path length
2.3 miles (3.7 km)
Path width
75 yards (69 m)
Deaths
0
Injuries
0
County
DeKalb County
Touchdown point
34.744, -85.619
Lift-off point
34.745, -85.578
Record number
1504032005-01

The damage survey

24 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 105 mph.

  • 5832 Alabama highway 75 flat rock or idler Alabama

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 cold front intersecting a warm and unstable environment led to a broken band of thunderstorms during the late afternoon and evening hours, some of which were supercellular in nature. These storms moved east-southeast at 35-45 mph and exited northern Alabama between 930 and 10 pm CDT. One tornado was confirmed in DeKalb County with a few narrow swaths of wind damage reported in other portions of north Alabama.

A tornado touched down in the Ider community of eastern DeKalb County, Alabama. The tornado first touched down along County Road 783. Numerous hardwood trees were snapped and uprooted. A small outbuilding was damaged near the intersection of County road 776. The tornado then tracked just north of County Road 776 before intersecting County Road 788. ||Damage to trees was fairly widespread in this area. Several homes or buildings also received minor roof or structural damage. The tornado reached its maximum intensity just west of Alabama Highway 75. One home there sustained significant roof damage with the majority of the roof removed. An anchored outbuilding was destroyed and several over homes sustained minor damage. Also, a power pole was snapped off and many large hardwood trees were snapped about 20 feet above the ground. ||The tornado then crossed Alabama Highway 75, snapping and uprooting trees along both sides of the road. The tornado began to weaken as it moved east-southeast, crossing County Road 372. Very minor roof damage was noted to a home and a few trees were uprooted. The tornado then dissipated on the east side of County Road 791 in the Cartersville, Alabama community after uprooting a few trees on the eastern slopes of Sand Mountain.

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.

The county was under a severe thunderstorm watch, issued at 23:50 UTC and running to 03:00 UTC.

Issued (UTC)ExpiredProductOffice
23:50 UTC03:00 UTCSevere Thunderstorm WatchHUN
01:52 UTC02:15 UTCSevere Thunderstorm WarningHUN
01:54 UTC02:30 UTCSevere Thunderstorm WarningHUN
02:10 UTC02:21 UTCTornado WarningHUN
02:26 UTC03:00 UTCSevere Thunderstorm WarningHUN
02:32 UTC03:00 UTCTornado WarningHUN
02:43 UTC02:55 UTCTornado WarningHUN

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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:38 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.

Nashville Metro, TN (KBNA), 00:00Z

2.1 hours before the tornado, 179 km from the path. April 4, 2015.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2015-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2 joules per kilogram, CIN -133, lifted condensation level 593 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Nashville Metro, TN at 00:00Z on 2015-04-04The 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 16 square meters per square second, 0 to 6 km bulk shear 65 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
2 J/kg
Mixed-layer CIN
-133 J/kg
Surface CAPE
32 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
65 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
107 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Nashville Metro, TN (KBNA), 12:00Z

9.9 hours after it, 179 km from the path. April 4, 2015.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 2015-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -91775, lifted condensation level 983 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Nashville Metro, TN at 12:00Z on 2015-04-04The 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 -152 square meters per square second, 0 to 6 km bulk shear 90 knots.1939587897117136Sfc1 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
0 J/kg
Mixed-layer CIN
-91775 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
983 m above ground
0-6 km bulk shear
90 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
-152 m²/s²
0-3 km storm-relative helicity
-99 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.1 K/km

Open this sounding in Storm Lab

The radar

The Northeast Alabama radar (KHTX), 49 km away, was scanning. The volume nearest the touchdown began at 02:05 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)ReportWhereCountyRemark
02:03 UTCTSTM WND DMG2 N IderDekalb, ALMANY TREES DOWN ON HIGHWAY 75, ABOUT 2 MILES NORTH OF IDER, CROSSING BETWEEN CARTERSVILLE AND IDER. POSSIBLE TORNADO.
02:24 UTCTSTM WND DMG2 N IderDekalb, ALDAMAGE TO A HOME AND GARAGE IN THE CARTERSVILLE AREA OUTSIDE OF IDER ALONG HWY 75. POSSIBLE TORNADO.
02:24 UTCTSTM WND DMGFyffeDekalb, ALMULTIPLE TREES DOWN IN THE FYFFE AREA.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2015 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

The other tornadoes of April 3, 2015

4 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 32:17 AM CDTEF0Labette, KS0.050
April 35:22 PM CDTEF0Williamson, TN5.675$20,000
April 38:15 PM CDTEF0DeKalb, AL0.930
April 310:10 PM EDTEF1Dade, GA0.130$5,000

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.