Tornadoes · United States · Colorado · 1965

F2 tornado, Weld County, Colorado, May 8, 1965

This F2 tornado ran 1.0 miles across Weld County on May 8, 1965, touching down at 3:00 AM GMT-6 and reaching 17 yards wide. It killed nobody, and did $5,000 to $50,000 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
May 8, 1965
Touchdown
3:00 AM GMT-6 (09:00 UTC)
Path length
1.0 miles (1.6 km)
Path width
17 yards (16 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Weld County
Touchdown point
40.770, -104.770
Record number
254

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

9.0 hours before the tornado, 164 km from the path. May 8, 1965.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 00:00Z on 1965-05-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 12 joules per kilogram, CIN -8, lifted condensation level 2970 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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 1965-05-08The 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 83 square meters per square second, 0 to 6 km bulk shear 69 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
12 J/kg
Mixed-layer CIN
-8 J/kg
Surface CAPE
122 J/kg
Mixed-layer LCL
2970 m above ground
0-6 km bulk shear
69 kt
0-1 km bulk shear
12 kt
0-1 km storm-relative helicity
83 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
9.6 K/km

Open this sounding in Storm Lab

Denver, CO (KDEN), 12:00Z

3.0 hours after it, 164 km from the path. May 8, 1965.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 1965-05-08Temperature 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 0, lifted condensation level 640 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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 1965-05-08The 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 135 square meters per square second, 0 to 6 km bulk shear 88 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
0 J/kg
Mixed-layer CIN
0 J/kg
Surface CAPE
7 J/kg
Mixed-layer LCL
640 m above ground
0-6 km bulk shear
88 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
141 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.7 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1965 tornado in ColoradoEvery tornado in Colorado since 1950Warnings in force in Colorado nowThe forecast where you are

The other tornadoes of May 8, 1965

37 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 82:15 PM GMT-5F1Waukesha, WI2.010$50,000 to $500,000
May 83:00 PM GMT-5F0Cotton, OK0.110$500 to $5,000
May 84:15 PM GMT-5F1Montgomery, KS1.5300$500 to $5,000
May 85:00 PM GMT-5F0Buffalo, SD0.1102
May 86:00 PM GMT-4F1Williamsburg, SC0.850$5,000 to $50,000
May 85:00 PM GMT-5F3Howard, NE10.210
May 85:00 PM GMT-5F1Osage, OK0.110$5,000 to $50,000
May 85:25 PM GMT-5F4Howard, NE78.910
May 85:30 PM GMT-5F2Rock, NE44.910
May 85:40 PM GMT-5F3Thayer, NE40.110
May 86:00 PM GMT-5F1Logan, NE89.810
May 86:00 PM GMT-5F1Cass, NE0.110
May 86:00 PM GMT-5F3Holt, NE44.810$5 million to $50 million
May 86:15 PM GMT-5F1Crawford, KS0.110$5,000 to $50,000
May 86:15 PM GMT-5F5Colome tornado, SD30.11,7601$500,000 to $5 million
May 86:23 PM GMT-5F2Tripp, SD0.120
May 86:30 PM GMT-5F2Brown, NE4.110
May 86:30 PM GMT-5F2Brown, NE9.010
May 86:30 PM GMT-5F4Hall, NE125.710453$5 million to $50 million
May 86:30 PM GMT-5F1Hamilton, NE0.110
May 86:35 PM GMT-5F1Hamilton, NE7.210
May 87:00 PM GMT-5F3Gregory, SD1.520$500 to $5,000
May 87:00 PM GMT-5F0Boyd, NE0.110
May 87:00 PM GMT-5F2Platte, NE24.010
May 87:30 PM GMT-5F2Miner, SD3.3243$5,000 to $50,000
May 87:30 PM GMT-5F1Sully, SD0.110
May 87:30 PM GMT-5F1Wayne, NE41.510
May 88:00 PM GMT-5F2Clay, SD4.510$5,000 to $50,000
May 88:00 PM GMT-5F2Brule, SD4.3100$5,000 to $50,000
May 88:00 PM GMT-5F0Potter, SD0.110
May 88:00 PM GMT-6F0Stanley, SD0.110
May 89:30 PM GMT-5F2Sebastian, AR5.11008$50,000 to $500,000
May 810:00 PM GMT-5F1McIntosh, OK0.110$500 to $5,000
May 810:10 PM GMT-5F0Love, OK0.110
May 810:32 PM GMT-5F0Potter, SD0.110
May 810:25 PM GMT-6F0Dewey, SD0.110
May 810:35 PM GMT-6F0Corson, SD0.110

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.