Tornadoes · United States · Nebraska · 1975

F3 tornado, Pierce, Cedar and Knox counties, Nebraska, May 6, 1975

This F3 tornado ran 44.8 miles across Pierce, Cedar and Knox counties on May 6, 1975, touching down at 2:15 PM CDT and reaching 90 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 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 mphthis tornado

    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
F3
Date
May 6, 1975
Touchdown
2:15 PM CDT (19:15 UTC)
Path length
44.8 miles (72.1 km)
Path width
90 yards (82 m)
Deaths
0
Injuries
0
Counties
Pierce, Cedar and Knox counties
Touchdown point
42.170, -97.470
Lift-off point
42.820, -97.500
Record number
306

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.

Omaha, NE (KOAX), 12:00Z

7.3 hours before the tornado, 160 km from the path. May 6, 1975.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 1975-05-06Temperature 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 -44738, lifted condensation level 3605 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Omaha, NE at 12:00Z on 1975-05-06The 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 103 square meters per square second, 0 to 6 km bulk shear 34 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
-44738 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3605 m above ground
0-6 km bulk shear
34 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

4.7 hours after it, 160 km from the path. May 7, 1975.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1975-05-07Temperature 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 -42052, lifted condensation level 3595 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 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, Omaha, NE at 00:00Z on 1975-05-07The 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 231 square meters per square second, 0 to 6 km bulk shear 54 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
-42052 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3595 m above ground
0-6 km bulk shear
54 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
231 m²/s²
0-3 km storm-relative helicity
266 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

Yankton (YKN), 48 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
18:00 UTC746290° 10 kt231002.4DZ
19:00 UTC726190° 20 kt301001.4DZ
20:00 UTC90° 20 kt301001

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

This ground now

The live radar over the trackEvery 1975 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

The other tornadoes of May 6, 1975

13 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 61:05 AM CDTF2West Carroll Parish, LA5.6332$5,000 to $50,000
May 67:00 AM EDTF1Talbot, MD0.110$5,000 to $50,000
May 612:05 PM CDTF0Brule, SD12.450$50,000 to $500,000
May 62:05 PM CDTF4Pierce, NE4.1300
May 62:30 PM CDTF0Knox, NE5.430$5,000 to $50,000
May 62:45 PM CDTF3Stanton, NE15.91671$50,000 to $500,000
May 62:46 PM CDTF1Bon Homme, SD0.110$50 to $500
May 63:10 PM CDTF0Bon Homme, SD0.110$50 to $500
May 64:00 PM CDTF0Saunders, NE3.417$500 to $5,000
May 64:30 PM CDTF0Dixon, NE3.080$5,000 to $50,000
May 64:33 PM CDTF4Sarpy, NE8.02673133$50,000 to $500,000
May 65:00 PM CDTF2Pottawattamie, IA12.8500$5,000 to $50,000
May 65:20 PM CDTF2Harrison, IA10.610$5,000 to $50,000

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.