EF0 tornado, Bar Nunn, Wyoming, July 26, 2018

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.

Rating

EF0

Date

July 26, 2018

Touchdown

3:32 PM MDT (21:32 UTC)

Lifted

3:33 PM MDT (21:33 UTC)

On the ground

1 minutes

Path length

0.2 miles (0.4 km)

Path width

20 yards (18 m)

Deaths

0

Injuries

0

County

Natrona County

Touchdown point

42.900, -106.320

Lift-off point

42.897, -106.317

Record number

1807261532-01

The combination of a stationary front over the area, a shortwave moving across the area and strong jet dynamics brought rounds of severe thunderstorms over northern and central Wyoming. The hardest hit town this day was Lovell where a combination of 70 mph winds and golf ball size hail produced widespread damage with hundreds of broken windows and many houses with damaged siding. Strong winds also downed many trees and limbs. The same storm produced 79 mph winds at the Greybull airport. Elsewhere, severe thunderstorms moved through Johnson and Natrona Counties. There were numerous reports of quarter to golf ball size hail from west of Buffalo through Midwest and into Casper. A weak landspout tornado also touched down north of Casper. Another storm produced quarter size hail in Thermopolis.

Two trained spotters photographed a landspout tornado to the north of Casper. The tornado remained over open county and caused no damage.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

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 Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 19:57 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 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.

Casper/Natrona International (CPR), 12 km from the path, in the two hours either side.

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

The Riverton/Lander radar (KRIW), 177 km away, was scanning. The volume nearest the touchdown began at 21:32 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.

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

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

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

2 more were confirmed in the United States that day.

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.