Tornadoes · United States · Oklahoma · 1991

F2 tornado, Kay County, Oklahoma, April 26, 1991

This F2 tornado ran 1.0 miles across Kay County on April 26, 1991, touching down at 6:45 AM CDT and reaching 100 yards wide. It killed nobody, 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 mphthis tornado

    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 mph

    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
F2
Date
April 26, 1991
Touchdown
6:45 AM CDT (11:45 UTC)
Path length
1.0 miles (1.6 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
Property damage
$50,000 to $500,000
County
Kay County
Touchdown point
36.680, -97.300
Record number
301

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)ExpiredProductOffice
10:57 UTC11:45 UTCSevere Thunderstorm WarningOUN
11:40 UTC12:45 UTCSevere Thunderstorm WarningOUN
12:41 UTC13:30 UTCSevere Thunderstorm WarningOUN
22:50 UTC23:15 UTCSevere Thunderstorm WarningOUN
23:19 UTC23:45 UTCTornado WarningOUN
23:50 UTC00:30 UTCSevere Thunderstorm WarningOUN
01:48 UTC02:45 UTCSevere Thunderstorm WarningOUN
02:41 UTC03:15 UTCSevere Thunderstorm WarningOUN

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 High Risk. The outlook in force was issued at 06:35 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.

Norman, OK (KOUN), 00:00Z

11.8 hours before the tornado, 163 km from the path. April 26, 1991.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 00:00Z on 1991-04-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 896 joules per kilogram, CIN -133, lifted condensation level 1066 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, Norman, OK at 00:00Z on 1991-04-26The 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 113 square meters per square second, 0 to 6 km bulk shear 33 knots.193958Sfc1 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
896 J/kg
Mixed-layer CIN
-133 J/kg
Surface CAPE
4031 J/kg
Mixed-layer LCL
1066 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
113 m²/s²
0-3 km storm-relative helicity
180 m²/s²
Significant tornado parameter
0.1
Supercell composite
4.7
0-3 km lapse rate
6.7 K/km

Open this sounding in Storm Lab

Norman, OK (KOUN), 12:00Z

0.2 hours after it, 163 km from the path. April 26, 1991.

Skew-T log-pSkew-T log-p diagram, Norman, OK at 12:00Z on 1991-04-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2265 joules per kilogram, CIN -6, lifted condensation level 595 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, Norman, OK at 12:00Z on 1991-04-26The 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 213 square meters per square second, 0 to 6 km bulk shear 39 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
2265 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
2452 J/kg
Mixed-layer LCL
595 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
33 kt
0-1 km storm-relative helicity
213 m²/s²
0-3 km storm-relative helicity
301 m²/s²
Significant tornado parameter
2.3
Supercell composite
12.2
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1991 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are

The other tornadoes of April 26, 1991

52 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 2610:30 AM CDTF1Jefferson Parish, LA0.210$5,000 to $50,000
April 2610:45 AM CDTF2Montgomery, KS6.0100$50,000 to $500,000
April 263:25 PM CDTF2Washington, KS3.51006$50,000 to $500,000
April 263:40 PM CDTF1Fillmore, NE1.050$5,000 to $50,000
April 263:45 PM CDTF0Chase, KS1.017$500 to $5,000
April 263:50 PM CDTF3Washington, KS to NE24.0200$50,000 to $500,000
April 264:10 PM CDTF0Morris, KS13.050$500,000 to $5 million
April 264:35 PM CDTF2Wabaunsee, KS44.0200$50,000 to $500,000
April 265:00 PM CDTF2Gage, NE4.0150$50,000 to $500,000
April 265:15 PM CDTF3Otoe, NE14.03502$500,000 to $5 million
April 265:20 PM CDTF0Harper, KS1.050$500 to $5,000
April 265:30 PM CDTF0Harper, KS16.050$500 to $5,000
April 265:47 PM CDTF1Sedgwick, KS2.050$5,000 to $50,000
April 265:57 PM CDTF5Andover tornado, KS46.044017225$50 million to $500 million
April 266:00 PM CDTF3Garfield, OK6.0350$50,000 to $500,000
April 266:10 PM CDTF1Sedgwick, KS16.050$5,000 to $50,000
April 266:15 PM CDTF0Pierce, NE0.120
April 266:15 PM CDTF0Garfield, OK0.120
April 266:30 PM CDTF4Garfield, OK66.01,5006$500,000 to $5 million
April 266:30 PM CDTF4Cowley, KS25.05001$5 million to $50 million
April 266:35 PM CDTF0Wabaunsee, KS9.020
April 267:00 PM CDTF2Cherokee, TX0.210$50,000 to $500,000
April 267:10 PM CDTF2Butler, KS21.01004$50,000 to $500,000
April 267:11 PM CDTF3Cherokee, TX3.02001$50,000 to $500,000
April 267:26 PM CDTF3Elk, KS14.020012$50,000 to $500,000
April 267:38 PM CDTF2Payne, OK6.5800$50,000 to $500,000
April 267:40 PM CDTF0Chase, KS1.050$500 to $5,000
April 267:40 PM CDTF2Rusk, TX3.0100$5,000 to $50,000
April 267:44 PM CDTF1Shelby, IA2.047$500 to $5,000
April 268:00 PM CDTF3Crawford, IA7.7150$500,000 to $5 million
April 268:00 PM CDTF2Rusk, TX0.210$50,000 to $500,000
April 268:10 PM CDTF4Pawnee, OK32.01,700124$500,000 to $5 million
April 268:22 PM CDTF1Rusk, TX0.210$500 to $5,000
April 268:27 PM CDTF1Osage, OK0.310
April 268:33 PM CDTF0Sedgwick, KS1.050$500 to $5,000
April 268:35 PM CDTF3Greenwood, KS15.050$500,000 to $5 million
April 268:54 PM CDTF1Shawnee, KS11.0204$5,000 to $50,000
April 269:00 PM CDTF2Dickinson, IA18.060$50,000 to $500,000
April 269:05 PM CDTF2Washington, OK6.0100110$50,000 to $500,000
April 269:25 PM CDTF2Jefferson, KS25.0272$500,000 to $5 million
April 269:45 PM CDTF4Rogers, OK4.01,30022$5 million to $50 million
April 2610:00 PM CDTF2Red River, TX0.210$50,000 to $500,000
April 2610:10 PM CDTF1Rogers, OK2.0303$50,000 to $500,000
April 2610:15 PM CDTF1Andrew, MO1.850$5,000 to $50,000
April 2610:19 PM CDTF1Red River, TX0.210$5,000 to $50,000
April 2610:20 PM CDTF0Montgomery, KS1.050$5,000 to $50,000
April 2610:30 PM CDTF2Red River, TX0.210$50,000 to $500,000
April 2611:10 PM CDTF2Wayne, IA9.060$50,000 to $500,000
April 2611:10 PM CDTF2Wayne, IA15.0772$500,000 to $5 million
April 2611:39 PM CDTF0Newton, MO0.250
April 2611:57 PM CDTF1Andrew, MO1.550$500 to $5,000
April 2612:05 AM CDTF0Jasper, MO0.110

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.