Tornadoes · United States · Utah · 2018

EF0 tornado, Snowville, Utah, May 28, 2018

This EF0 tornado ran 0.1 miles across Box Elder County on May 28, 2018, touching down at 3:15 PM MDT and reaching 5 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 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. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 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
EF0
Date
May 28, 2018
Touchdown
3:15 PM MDT (21:15 UTC)
Lifted
3:17 PM MDT (21:17 UTC)
On the ground
2 minutes
Path length
0.1 miles (0.2 km)
Path width
5 yards (5 m)
Deaths
0
Injuries
0
County
Box Elder County
Touchdown point
41.970, -112.714
Lift-off point
41.970, -112.712
Record number
1805281515-01

What the Weather Service recorded

Strong thunderstorms developed across Utah on May 28 through May 30, with some of these storms producing tornadoes and severe wind gusts.

A brief tornado touchdown was observed and photographed near Snowville. No damage was reported. Time, exact location, and path width are all estimated.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

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 forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 19:37 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

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

9.3 hours before the tornado, 149 km from the path. May 28, 2018.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 12:00Z on 2018-05-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 43 joules per kilogram, CIN -157, lifted condensation level 995 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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, Salt Lake City I, UT at 12:00Z on 2018-05-28The 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 -27 square meters per square second, 0 to 6 km bulk shear 4 knots.1939Sfc1 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
43 J/kg
Mixed-layer CIN
-157 J/kg
Surface CAPE
83 J/kg
Mixed-layer LCL
995 m above ground
0-6 km bulk shear
4 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
-27 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.8 K/km

Open this sounding in Storm Lab

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

2.7 hours after it, 149 km from the path. May 29, 2018.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 00:00Z on 2018-05-29Temperature 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 -86266, lifted condensation level 2125 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, Salt Lake City I, UT at 00:00Z on 2018-05-29The 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 6 square meters per square second, 0 to 6 km bulk shear 3 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
0 J/kg
Mixed-layer CIN
-86266 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
2125 m above ground
0-6 km bulk shear
3 kt
0-1 km bulk shear
7 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.7 K/km

Open this sounding in Storm Lab

The radar

The Salt Lake City radar (KMTX), 82 km away, was scanning. The volume nearest the touchdown began at 21:16 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
21:15 UTCTORNADOSnowvilleBox Elder, UTBRIEF TOUCHDOWN REPORTED WITH PICTURES TO BROADCAST MEDIA NEAR SNOWVILLE. NO DAMAGE OR INJURIES.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2018 tornado in UtahEvery tornado in Utah since 1950Warnings in force in Utah nowThe forecast where you are

The other tornadoes of May 28, 2018

28 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 283:06 PM EDTEF0Calhoun, SC0.3150
May 281:10 PM MDTEF0Wasatch, UT0.35
May 281:15 PM MDTEF0Jackson, CO0.150
May 282:19 PM CDTEF0Graham, KS4.5100
May 282:20 PM CDTEF0Pocahontas, IA0.930
May 283:00 PM MDTEF0Fremont, WY0.520
May 283:39 PM MDTEF0Sweetwater, WY3.525
May 284:19 PM MDTEF0Kit Carson, CO0.0100
May 284:22 PM MDTEF0Washington, CO0.050
May 285:00 PM MDTEF0Washington, CO0.050
May 285:00 PM MDTEF0Washington, CO0.050
May 285:00 PM MDTEF0Kit Carson, CO1.3150
May 285:10 PM MDTEF0Kit Carson, CO2.6200$60,000
May 285:10 PM MDTEF0Kit Carson, CO1.8150
May 285:10 PM MDTEF0Morgan, CO0.050
May 285:11 PM MDTEF0Washington, CO0.150
May 285:15 PM MDTEF0Washington, CO3.6100
May 285:23 PM MDTEF0Washington, CO0.050
May 285:26 PM MDTEF0Kit Carson, CO0.0150
May 285:29 PM MDTEF0Washington, CO0.050
May 285:34 PM MDTEF0Weld, CO0.050
May 285:35 PM MDTEF0Kit Carson, CO0.0100
May 285:37 PM MDTEF0Weld, CO0.050
May 285:42 PM MDTEF1Washington, CO0.050
May 286:24 PM MDTEF0Morgan, CO0.050
May 286:32 PM MDTEF0Morgan, CO0.050
May 287:41 PM CDTEF0Texas, OK0.350
May 288:21 PM CDTEF1Texas, OK2.0200

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.