Tornadoes · United States · Wyoming · 2009
EF2 tornado, La Grange, Wyoming, June 5, 2009
This EF2 tornado ran 8.3 miles across Goshen County on June 5, 2009, touching down at 4:02 PM MDT and reaching 100 yards wide. It killed nobody, and did $10,000 of property damage.
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.
EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
EF2111 to 135 mphthis tornado
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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
- EF2
- Date
- June 5, 2009
- Touchdown
- 4:02 PM MDT (22:02 UTC)
- Lifted
- 4:31 PM MDT (22:31 UTC)
- On the ground
- 29 minutes
- Path length
- 8.3 miles (13.4 km)
- Path width
- 100 yards (91 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $10,000
- County
- Goshen County
- Touchdown point
- 41.630, -104.383
- Lift-off point
- 41.613, -104.224
- Record number
- 0906051602-01
The damage survey
5 damage points were recorded along this path by NWS CYS, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF2. The highest wind the damage implies is 118 mph.
Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.
What the Weather Service recorded
Scattered severe thunderstorms produced large hail and a tornado over parts of southeast Wyoming.
A widely observed tornado moved across open country of far southern Goshen county. Only minor damage was caused, mainly to a few power poles and trees.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
13 minutes of warning. NWS CYS issued a tornado warning for this county at 21:49 UTC, 13 minutes before the tornado touched down, in force until 22:15 UTC.
The county was under a tornado watch, issued at 20:50 UTC and running to 23:22 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 20:47 UTC | 21:45 UTC | Severe Thunderstorm Warning | CYS |
| 20:50 UTC | 23:22 UTC | Tornado Watch | CYS |
| 21:06 UTC | 22:00 UTC | Severe Thunderstorm Warning | CYS |
| 21:27 UTC | 22:00 UTC | Tornado Warning | CYS |
| 21:49 UTC | 22:15 UTC | Tornado Warning | CYS |
| 22:10 UTC | 22:45 UTC | Tornado Warning | CYS |
| 22:42 UTC | 23:03 UTC | Tornado Warning | CYS |
| 02:41 UTC | 03:30 UTC | Severe Thunderstorm Warning | CYS |
| 03:30 UTC | 04:05 UTC | Severe Thunderstorm Warning | CYS |
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 Slight Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 20:01 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.
Denver, CO (KDNR), 12:00Z
10.0 hours before the tornado, 215 km from the path. June 5, 2009.
- Mixed-layer CAPE
- 997 J/kg
- Mixed-layer CIN
- -190 J/kg
- Surface CAPE
- 441 J/kg
- Mixed-layer LCL
- 1029 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 57 m²/s²
- 0-3 km storm-relative helicity
- 65 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
- 0-3 km lapse rate
- 5.0 K/km
Denver, CO (KDNR), 00:00Z
2.0 hours after it, 215 km from the path. June 6, 2009.
- Mixed-layer CAPE
- 2239 J/kg
- Mixed-layer CIN
- -16 J/kg
- Surface CAPE
- 3473 J/kg
- Mixed-layer LCL
- 1693 m above ground
- 0-6 km bulk shear
- 57 kt
- 0-1 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 118 m²/s²
- 0-3 km storm-relative helicity
- 334 m²/s²
- Significant tornado parameter
- 1.2
- Supercell composite
- 18.4
- 0-3 km lapse rate
- 8.6 K/km
The radar
The Cheyenne radar (KCYS), 67 km away, was scanning. The volume nearest the touchdown began at 22:02 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 20:58 UTC | HAIL 0.5 | 1 Ne Chugwater | Platte, WY | |
| 20:58 UTC | HAIL 1 | 1 E Chugwater | Platte, WY | REPORTER CALLED THE OFFICE AT 1545L TO REPORT LOCAL FLOODING WITH DRIFTS OF HAIL. PEOPLE IN THE AREA WHEN THE HAIL FELL REPORTED HAIL SIZES OF QUARTER TO GOLFBALL. |
| 21:10 UTC | HAIL 0.25 | Chugwater | Platte, WY | LOTS OF RAIN. |
| 21:32 UTC | HAIL 0.5 | 14 W Hawk Springs | Goshen, WY | |
| 21:34 UTC | HAIL 1.75 | 1 E Chugwater | Platte, WY | OBSERVER CALLED THE OFFICE TO REPORT LOCAL FLOODING WITH DRIFTS OF HAIL. PEOPLE IN THE AREA WHEN THE HAIL FELL REPORTED HAIL SIZES OF QUARTER TO GOLFBALL. |
| 21:47 UTC | HAIL 1.75 | 7 E Chugwater | Platte, WY | HAIL VARIED IN SIZE FROM GOLFBALL TO MARBLE. |
| 22:07 UTC | TORNADO 2 | 11 W La Grange | Goshen, WY | TORNADO TOUCHDOWN. MOVING TO THE EAST. |
| 22:07 UTC | TORNADO | 11 W La Grange | Goshen, WY | MOVING TO THE EAST. |
| 22:10 UTC | HAIL 4.25 | 15 Nw La Grange | Goshen, WY | SOME HAIL AS LARGE AS 4.5 INCHES. |
| 22:31 UTC | TORNADO 2 | 3 Wsw La Grange | Goshen, WY | TORNADO JUST DISSIPATED. |
| 22:31 UTC | TORNADO | 3 Wsw La Grange | Goshen, WY | TORNADO JUST DISSIPATED. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2009 tornado in WyomingEvery tornado in Wyoming since 1950Warnings in force in Wyoming nowThe forecast where you are
The other tornadoes of June 5, 2009
3 more were confirmed in the United States that day.
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.