Tornadoes · United States · Arkansas · 2011

EF1 tornado, Loy, Arkansas, April 14, 2011

This EF1 tornado ran 0.5 miles across Madison County on April 14, 2011, touching down at 12:10 AM CDT and reaching 100 yards wide. It killed nobody, and did $15,000 of property damage.

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 14, 2011
Touchdown
12:10 AM CDT (05:10 UTC)
Lifted
12:11 AM CDT (05:11 UTC)
On the ground
1 minutes
Path length
0.5 miles (0.8 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
Property damage
$15,000
County
Madison County
Touchdown point
36.007, -93.525
Lift-off point
36.011, -93.520
Record number
1104142310-01

What the Weather Service recorded

Severe thunderstorms that developed along a dry line during the early evening over eastern Oklahoma moved into northwestern Arkansas by late evening. These thunderstorms produced several tornadoes, large hail, and damaging wind gusts as they moved through the region.

A tornado damaged a home and uprooted trees. Maximum estimated wind in the tornado based on the damage was about 95 mph.

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.

The county was under a tornado watch, issued at 02:10 UTC and running to 05:28 UTC.

Issued (UTC)ExpiredProductOffice
02:10 UTC05:28 UTCTornado WatchTSA

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 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:59 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.

Springfield, MO (KSGF), 00:00Z

5.2 hours before the tornado, 102 km from the path. April 15, 2011.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 00:00Z on 2011-04-15Temperature 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 -90630, lifted condensation level 2194 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Springfield, MO at 00:00Z on 2011-04-15The 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 81 square meters per square second, 0 to 6 km bulk shear 37 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
0 J/kg
Mixed-layer CIN
-90630 J/kg
Surface CAPE
44 J/kg
Mixed-layer LCL
2194 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
24 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
249 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3
0-3 km lapse rate
7.0 K/km

Open this sounding in Storm Lab

Springfield, MO (KSGF), 12:00Z

6.8 hours after it, 102 km from the path. April 15, 2011.

Skew-T log-pSkew-T log-p diagram, Springfield, MO at 12:00Z on 2011-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 412 joules per kilogram, CIN -9, lifted condensation level 572 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, Springfield, MO at 12:00Z on 2011-04-15The 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 112 square meters per square second, 0 to 6 km bulk shear 28 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
412 J/kg
Mixed-layer CIN
-9 J/kg
Surface CAPE
333 J/kg
Mixed-layer LCL
572 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.3
0-3 km lapse rate
6.4 K/km

Open this sounding in Storm Lab

The surface observations

Harrison/Boone Co. (HRO), 43 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
03:53 UTC6653130° 8 kt1004.1-TSRA
04:53 UTC5957.2260° 3 kt1003.7VCTS -RA BR
05:03 UTC60.857.2 1003.7+RA BR
05:11 UTC5957.2 1004.4+TSRA BR
05:28 UTC5957.2 1003.4VCTS +RA BR
06:02 UTC5959250° 10 kt1003.4VCTS +RA BR
06:23 UTC55.453.6300° 10 kt191003.4+TSRA BR
06:34 UTC55.453.6290° 7 kt1003.4TSRA BR
06:53 UTC5554300° 4 kt1003+TSRA BR
07:08 UTC53.653.630° 8 kt1001.7+TSRA BR

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Western Arkansas radar (KSRX), 110 km away, was scanning. The volume nearest the touchdown began at 05:07 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.

This ground now

The live radar over the trackEvery 2011 tornado in ArkansasEvery tornado in Arkansas since 1950Warnings in force in Arkansas nowThe forecast where you are

The other tornadoes of April 14, 2011

47 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 144:12 PM CDTEF0Osage, OK0.440
April 144:42 PM CDTEF0Lincoln, OK0.340
April 144:45 PM CDTEF0Saline, KS1.660$45,000
April 145:00 PM CDTEF2Osage, OK1.0275$25,000
April 145:02 PM CDTEF0Cowley, KS2.2125
April 145:16 PM CDTEF0Chautauqua, KS0.560
April 145:23 PM CDTEF0Saline, KS0.460
April 145:24 PM CDTEF1Pontotoc, OK1.050$8,000
April 145:38 PM CDTEF0Okfuskee, OK0.250
April 145:39 PM CDTEF0Washington, OK0.150
April 145:44 PM CDTEF0Washington, OK0.150
April 146:03 PM CDTEF1Marshall, OK14.0300
April 146:05 PM CDTEF1Okfuskee, OK11.4100
April 146:11 PM CDTEF1Washington, OK1.6200$20,000
April 146:11 PM CDTEF0Cowley, KS0.250
April 146:12 PM CDTEF0Clay, KS0.125
April 144:15 PM PDTEF0Morrow, OR0.210$500
April 146:25 PM CDTEF0Johnston, OK0.2100
April 146:33 PM CDTEF0Okfuskee, OK0.150
April 147:14 PM CDTEF1Pittsburg, OK5.5300
April 147:20 PM CDTEF3Atoka, OK17.01,320240
April 147:21 PM CDTEF1Atoka, OK4.0100$10,000
April 147:47 PM CDTEF2Delaware, OK0.51003$100,000
April 148:04 PM CDTEF0Atoka, OK7.0125
April 148:12 PM CDTEF0Pushmataha, OK0.150
April 148:12 PM CDTEF1Pushmataha, OK3.0400$10,000
April 148:18 PM CDTEF1Wagoner, OK1.8290$40,000
April 148:28 PM CDTEF1Latimer, OK4.6600$25,000
April 148:35 PM CDTEF2Pushmataha, OK7.01,000
April 148:36 PM CDTEF1Atoka, OK2.0400$20,000
April 148:46 PM CDTEF1Atoka, OK4.0500$30,000
April 148:50 PM CDTEF1Pushmataha, OK1.075
April 148:58 PM CDTEF1Atoka, OK14.31,100$50,000
April 148:59 PM CDTEF1Atoka, OK0.5125$10,000
April 149:08 PM CDTEF0Latimer, OK6.0500
April 149:23 PM CDTEF1LeFlore, OK7.04403$40,000
April 149:35 PM CDTEF1LeFlore, OK1.5300$10,000
April 1410:10 PM CDTEF1Sebastian, AR0.5150$100,000
April 1410:33 PM CDTEF0McCurtain, OK1.775$500
April 1410:35 PM CDTEF1Crawford, AR3.0250$15,000
April 1410:46 PM CDTEF0Fannin, TX1.5100$35,000
April 1411:02 PM CDTEF0McCurtain, OK4.675$10,000
April 1411:07 PM CDTEF1Polk, AR0.575$350,000
April 1411:08 PM CDTEF1Franklin, AR4.83502$30,000
April 1411:12 PM CDTEF1Yell, AR0.825$25,000
April 1411:35 PM CDTEF1Yell, AR2.175$75,000
April 1411:37 PM CDTEF0McCurtain, OK1.275

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.