EF1 tornado, Kansas to Prospect, Alabama, April 11, 2013

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

April 11, 2013

Touchdown

2:45 PM CDT (19:45 UTC)

Lifted

2:51 PM CDT (19:51 UTC)

On the ground

6 minutes

Path length

5.5 miles (8.8 km)

Path width

500 yards (457 m)

Deaths

0

Injuries

0

County

Walker County

Touchdown point

33.920, -87.536

Lift-off point

33.963, -87.458

Record number

1304111345-01

63 damage points were recorded along this path by NWS BMX and NWS HUN, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 110 mph.

• Multiple pine trees snapped in a ~25 yd wide path
• multiple pine trees snapped & uprooted, including a few snapped at the base atop a small ridge. most others in the valley snapped 30+ feet aloft
• multiple trees in swamp snapped (some old, most fresh)
• multiple trees snapped/uprooted on shore of smith lake, in confined area, laying in multiple directions

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

Severe thunderstorms ahead of and along a cold front moved across Central Alabama on Thursday, April 11th. Storms along the cold front formed into a quasi-linear convective system, causing wind damage and producing seven tornadoes across the area. Ahead of the line, strong daytime heating and increasing instabilities coupled with strong diffluence aloft created prime conditions for discrete thunderstorms to form. These storms caused wind damage across portions of northeast Central Alabama during the late afternoon.

National Weather Service meteorologists surveyed the damage in northwest Walker County and have determined that the damage was due to an EF-1 tornado, with maximum winds of 86 mph. The tornado touched down approximately 3/4 of a mile southwest of Dogtown Road, near Seamore Mountain, in the Mill Creek watershed. The tornado tracked northeast and crossed Dogtown Road where it uprooted several trees. The tornado continued northeast and crossed Highway 78 and Ritter Road, where the most significant damage occurred. Dozens of trees were uprooted and one single family home had portions of its roof and roof decking removed. The tornado continued northeast and crossed Nix Road, Nauvoo Road, Jagger Road, Johnson Road, and Slick Lizzard Road. Some minor structural damage was observed along these roads along with tree damage. The tornado finally lifted northeast of Slick Lizzard Road before it crossed Highway 5. This damage could not be linked to the tornado in southern Winston County at Poplar Springs.

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.

The county was under a tornado watch, issued at 17:00 UTC and running to 21:38 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 Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:21 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 Columbus AFB radar (KGWX), 77 km away, was scanning. The volume nearest the touchdown began at 19:45 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 2013 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

13 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.