Tornadoes · United States · Colorado · 1986

F1 tornado, Yuma County, Colorado, May 14, 1986

This F1 tornado ran 0.5 miles across Yuma County on May 14, 1986, touching down at 8:35 PM MDT and reaching 30 yards wide. It killed nobody.

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 mphthis tornado

    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 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
F1
Date
May 14, 1986
Touchdown
8:35 PM MDT (02:35 UTC)
Path length
0.5 miles (0.8 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Yuma County
Touchdown point
39.600, -102.520
Record number
273

The warnings

30 minutes of warning. NWS BOU issued a tornado warning for this county at 02:05 UTC, 30 minutes before the tornado touched down, in force until 02:40 UTC.

Issued (UTC)ExpiredProductOffice
02:05 UTC02:40 UTCTornado WarningBOU

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 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.

Denver, CO (KDEN), 00:00Z

2.6 hours before the tornado, 68 km from the path. May 15, 1986.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 00:00Z on 1986-05-15Temperature 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 -135, lifted condensation level 2618 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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, Denver, CO at 00:00Z on 1986-05-15The 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 -1 square meters per square second, 0 to 6 km bulk shear 42 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
2 J/kg
Mixed-layer CIN
-135 J/kg
Surface CAPE
254 J/kg
Mixed-layer LCL
2618 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0
0-3 km lapse rate
8.9 K/km

Open this sounding in Storm Lab

Denver, CO (KDEN), 12:00Z

9.4 hours after it, 68 km from the path. May 15, 1986.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 1986-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 11 joules per kilogram, CIN -87, lifted condensation level 892 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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, Denver, CO at 12:00Z on 1986-05-15The 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 -18 square meters per square second, 0 to 6 km bulk shear 44 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
11 J/kg
Mixed-layer CIN
-87 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
892 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
91 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

The surface observations

St Francis (SYF), 65 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
01:00 UTC6550100° 27 kt371005.1
02:00 UTC6246120° 23 kt311005.1
03:00 UTC5947150° 17 kt1005.8
04:00 UTC5947200° 10 kt1008.5

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

This ground now

The live radar over the trackEvery 1986 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of May 14, 1986

19 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 142:13 PM CDTF0Nowata, OK1.050
May 143:17 PM EDTF0Pasco, FL1.030$500 to $5,000
May 142:30 PM CDTF0Dallam, TX0.210
May 142:30 PM CDTF0Randall, TX3.050
May 143:00 PM CDTF0Stanton, KS0.3100
May 143:05 PM CDTF1Oklahoma, OK0.250
May 143:08 PM CDTF0Armstrong, TX0.230
May 143:29 PM CDTF1Jackson, OK6.0300
May 143:33 PM CDTF0Stanton, KS0.5100
May 143:42 PM CDTF1Jackson, OK6.0300$50,000 to $500,000
May 144:05 PM CDTF1Tillman, OK1.173$50,000 to $500,000
May 144:09 PM CDTF2Kiowa, OK3.0500$50,000 to $500,000
May 145:30 PM CDTF0Baylor, TX1.010
May 146:26 PM CDTF1Okfuskee, OK2.0150$5,000 to $50,000
May 146:49 PM CDTF1Garvin, OK0.523
May 147:30 PM CDTF3Archer, TX20.02504$500,000 to $5 million
May 148:42 PM CDTF0Montague, TX0.210
May 148:35 PM MDTF1Yuma, CO0.530
May 148:35 PM MDTF1Yuma, CO0.530

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.