EF1 tornado, Four Corners to Deerfield, Wyoming, June 10, 2008

1. EF065 to 85 mph

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

2. EF186 to 110 mphthis tornado

   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

EF1

Date

June 10, 2008

Touchdown

7:50 PM CDT (00:50 UTC)

Lifted

8:06 PM CDT (01:06 UTC)

On the ground

16 minutes

Path length

7.2 miles (11.6 km)

Path width

400 yards (366 m)

Deaths

0

Injuries

0

Counties

Weston and Pennington counties

Touchdown point

44.042, -104.102

Lift-off point

44.112, -104.000

Record number

0806101850-01

A supercell thunderstorm developed over northeastern Weston County. The storm produced hail to golf ball size and a tornado.

A severe thunderstorm moved from northeastern Wyoming into the central Black Hills and produced a tornado and large hail.

A tornado touched down near Beaver Creek Road southeast of Four Corners and traveled northeastward into South Dakota. The only damage it caused was blown down and snapped trees. Time of the tornado was estimated from Doppler Radar.

A tornado touched southeast of Four Corners, Wyoming and traveled northeastward into the Black Hills of far western South Dakota. It blew down and snapped almost 600 acres of trees on the Black Hills National Forest. The tornado track was determined from a US Forest Service aerial survey; time of the tornado was estimated from Doppler Radar.

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 Slight Risk. The outlook in force was issued at 22:30 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.

The Rapid City radar (KUDX), 98 km away, was scanning. The volume nearest the touchdown began at 00:50 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 2008 tornado in WyomingEvery tornado in Wyoming since 1950Warnings in force in Wyoming nowThe forecast where you are

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.