Tornadoes · United States · Oklahoma · 1977

F4 tornado, Cimarron and Baca counties, Oklahoma and Colorado, May 18, 1977

This F4 tornado ran 38.6 miles across Cimarron and Baca counties on May 18, 1977, touching down at 1:50 PM CDT and reaching 440 yards wide. It killed nobody, and did $500,000 to $5 million 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 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 mphthis tornado

    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
F4
Date
May 18, 1977
Touchdown
1:50 PM CDT (18:50 UTC)
Path length
38.6 miles (62.1 km)
Path width
440 yards (402 m)
Deaths
0
Injuries
0
Property damage
$500,000 to $5 million
Counties
Cimarron and Baca counties
Touchdown point
36.650, -102.400
Lift-off point
37.130, -102.070
Record number
287

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.

Amarillo Airport, TX (KAMA), 12:00Z

6.8 hours before the tornado, 191 km from the path. May 18, 1977.

Skew-T log-pSkew-T log-p diagram, Amarillo Airport, TX at 12:00Z on 1977-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1595 joules per kilogram, CIN -80, lifted condensation level 838 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, Amarillo Airport, TX at 12:00Z on 1977-05-18The 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 52 square meters per square second, 0 to 6 km bulk shear 16 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
1595 J/kg
Mixed-layer CIN
-80 J/kg
Surface CAPE
2985 J/kg
Mixed-layer LCL
838 m above ground
0-6 km bulk shear
16 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.4 K/km

Open this sounding in Storm Lab

Amarillo Airport, TX (KAMA), 00:00Z

5.2 hours after it, 191 km from the path. May 19, 1977.

Skew-T log-pSkew-T log-p diagram, Amarillo Airport, TX at 00:00Z on 1977-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 2271 joules per kilogram, CIN -26, lifted condensation level 1351 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, Amarillo Airport, TX at 00:00Z on 1977-05-19The 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 267 square meters per square second, 0 to 6 km bulk shear 44 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
2271 J/kg
Mixed-layer CIN
-26 J/kg
Surface CAPE
4057 J/kg
Mixed-layer LCL
1351 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
267 m²/s²
0-3 km storm-relative helicity
432 m²/s²
Significant tornado parameter
2.4
Supercell composite
26.8
0-3 km lapse rate
8.3 K/km

Open this sounding in Storm Lab

This ground now

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

The other tornadoes of May 18, 1977

24 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 182:30 PM CDTF2Cimarron, OK16.150$50 to $500
May 182:40 PM CDTF1McLean, ND5.410$50,000 to $500,000
May 183:00 PM CDTF0Hayes, NE0.230
May 183:21 PM CDTF0Ward, ND0.110
May 183:25 PM CDTF2Morton, KS117.250$500,000 to $5 million
May 183:28 PM CDTF1Calhoun, IA1.020$500 to $5,000
May 183:40 PM MDTF1Arthur, NE0.550$50,000 to $500,000
May 183:45 PM MDTF1Grant, NE0.330$5,000 to $50,000
May 185:00 PM CDTF1Lincoln, NE0.230$5,000 to $50,000
May 184:30 PM MDTF3Cherry, NE18.850$5,000 to $50,000
May 184:30 PM MDTF2Cherry, NE19.750$5,000 to $50,000
May 187:00 PM CDTF0Crosby, TX1.020
May 187:00 PM CDTF0Crosby, TX1.020
May 187:00 PM CDTF0Crosby, TX1.020
May 187:40 PM CDTF0Crosby, TX0.520
May 188:15 PM CDTF1Furnas, NE0.120$500 to $5,000
May 187:20 PM MDTF1Dewey, SD0.110$500 to $5,000
May 188:25 PM CDTF1Dickens, TX2.020under $50
May 188:30 PM CDTF1Dawson, NE0.220$5,000 to $50,000
May 189:10 PM CDTF0Cavalier, ND0.110
May 188:20 PM MDTF0Corson, SD0.110
May 189:31 PM CDTF0Buffalo, NE0.230
May 1810:05 PM CDTF1Dickens, TX0.520under $50
May 1811:25 PM CDTF1Antelope, NE0.530$500 to $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.