Tornadoes · United States · Utah · 1989

F0 tornado, Davis County, Utah, May 11, 1989

This F0 tornado ran 0.2 miles across Davis County on May 11, 1989, touching down at 5:45 PM MDT and reaching 10 yards wide. It killed nobody, and did under $50 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 mphthis tornado

    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 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
F0
Date
May 11, 1989
Touchdown
5:45 PM MDT (23:45 UTC)
Path length
0.2 miles (0.3 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
Property damage
under $50
County
Davis County
Touchdown point
41.120, -111.970
Record number
213

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

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.

Salt Lake City I, UT (KSLC), 12:00Z

11.8 hours before the tornado, 38 km from the path. May 11, 1989.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 12:00Z on 1989-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 54 joules per kilogram, CIN -51, lifted condensation level 1216 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, Salt Lake City I, UT at 12:00Z on 1989-05-11The 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 -78 square meters per square second, 0 to 6 km bulk shear 46 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
54 J/kg
Mixed-layer CIN
-51 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1216 m above ground
0-6 km bulk shear
46 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
-78 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1
0-3 km lapse rate
6.2 K/km

Open this sounding in Storm Lab

Salt Lake City I, UT (KSLC), 00:00Z

0.2 hours after it, 38 km from the path. May 12, 1989.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 00:00Z on 1989-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 8 joules per kilogram, CIN -1, lifted condensation level 797 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 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, Salt Lake City I, UT at 00:00Z on 1989-05-12The 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 -82 square meters per square second, 0 to 6 km bulk shear 45 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
8 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
290 J/kg
Mixed-layer LCL
797 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
-82 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.3
0-3 km lapse rate
6.6 K/km

Open this sounding in Storm Lab

The surface observations

Hill Afb/Ogden (HIF), 1 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:00 UTC6542330° 20 kt291005.1
22:03 UTC330° 20 kt241004.7-SHRA
23:00 UTC6041330° 18 kt261005.1TS
23:25 UTC240° 20 kt321007.1FC
00:00 UTC4938320° 8 kt1008.8TSRA
00:20 UTC10° 6 kt1008.8SHRA
01:00 UTC504150° 4 kt1009.1-SHRA

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

This ground now

The live radar over the trackEvery 1989 tornado in UtahEvery tornado in Utah since 1950Warnings in force in Utah nowThe forecast where you are

The other tornadoes of May 11, 1989

6 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 115:12 PM CDTF1Pecos, TX1.040
May 115:24 PM CDTF1Pecos, TX1.560
May 114:55 PM MDTF1Eddy, NM10.050
May 117:22 PM CDTF0Midland, TX0.540
May 119:02 PM MDTF0Custer, MT0.210$50,000 to $500,000
May 119:06 PM MDTF1Lea, NM5.023$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.