Tornadoes · United States · Oklahoma · 2011
EF0 tornado, Grainola to Boulangerville, Oklahoma, June 18, 2011
From Grainola to Boulangerville, this EF0 tornado ran 0.1 miles across Osage County on June 18, 2011, touching down at 7:29 PM CDT and reaching 50 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.
EF065 to 85 mphthis tornado
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 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.
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
- EF0
- Date
- June 18, 2011
- Touchdown
- 7:29 PM CDT (00:29 UTC)
- Path length
- 0.1 miles (0.2 km)
- Path width
- 50 yards (46 m)
- Deaths
- 0
- Injuries
- 0
- County
- Osage County
- Touchdown point
- 36.961, -96.546
- Lift-off point
- 36.961, -96.546
- Record number
- 1106181829-01
What the Weather Service recorded
A dry line advanced eastward into eastern Oklahoma on the evening of the 18th. An isolated supercell thunderstorm developed along this boundary and moved across several counties of far northeastern Oklahoma. The storm produced several tornadoes over open country and large hail up to golfball size.
Storm chasers witnessed a brief tornado over open country. The tornado resulted in no known damage.
Storm chasers witnessed a brief tornado over open country. The tornado resulted in no known damage.
Storm chasers and at least one off-duty NWS meteorologist witnessed a tornado over open country. The tornado resulted in no known damage.
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. One was issued for the county at another hour that day.
The county was under a severe thunderstorm watch, issued at 23:05 UTC and running to 06:50 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 23:05 UTC | 06:50 UTC | Severe Thunderstorm Watch | TSA |
| 23:59 UTC | 01:00 UTC | Severe Thunderstorm Warning | TSA |
| 00:35 UTC | 01:15 UTC | Tornado Warning | TSA |
| 00:48 UTC | 01:45 UTC | Severe Thunderstorm Warning | TSA |
| 01:04 UTC | 01:45 UTC | Tornado Warning | TSA |
| 01:33 UTC | 01:57 UTC | Tornado Warning | TSA |
| 01:37 UTC | 02:15 UTC | Severe Thunderstorm Warning | TSA |
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 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 21:16 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.
Lamont, OK (KLMN), 00:00Z
0.5 hours before the tornado, 91 km from the path. June 19, 2011.
- Mixed-layer CAPE
- 3821 J/kg
- Mixed-layer CIN
- -50 J/kg
- Surface CAPE
- 3292 J/kg
- Mixed-layer LCL
- 2143 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- 49 m²/s²
- 0-3 km storm-relative helicity
- 150 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 12.3
- 0-3 km lapse rate
- 8.1 K/km
Lamont, OK (KLMN), 12:00Z
11.5 hours after it, 91 km from the path. June 19, 2011.
- Mixed-layer CAPE
- 742 J/kg
- Mixed-layer CIN
- -629 J/kg
- Surface CAPE
- 431 J/kg
- Mixed-layer LCL
- 1910 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 319 m²/s²
- 0-3 km storm-relative helicity
- 394 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 2.8 K/km
The radar
The Wichita radar (KICT), 111 km away, was scanning. The volume nearest the touchdown began at 00:29 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 |
|---|---|---|---|---|
| 01:09 UTC | TORNADO | 7 Nnw Bigheart | Osage, OK | LIVE VIDEO OF BRIEF TORNADO WAS BROADCASTED BY KJRH |
| 01:10 UTC | FUNNEL CLOUD | 8 Ne Bigheart | Osage, OK | STORM CHASER OBSERVED A FUNNEL CLOUD LOWER HALF WAY TO THE GROUND AND LIFT. |
| 01:15 UTC | HAIL 0.88 | 7 N Bigheart | Osage, OK | DELAYED REPORT. |
| 01:25 UTC | TORNADO | 7 W Hulah | Osage, OK | SEVERAL STORMS CHASERS...STORM SPOTTERS AND AT LEAST ONE OFF DUTY NWS METEOROLOGIST WITNESSED THIS TORNADO. IT LASTED 10 TO 15 MINUTES AND PRODUCED NO KNOWN DAMAGE. |
| 02:10 UTC | HAIL 1.75 | 2 Nw Copan | Washington, OK | SPOTTER REPORTED GOLD BALL HAIL IN THE COPAN LAKE AREA. |
From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.
This ground now
The live radar over the trackEvery 2011 tornado in OklahomaEvery tornado in Oklahoma since 1950Warnings in force in Oklahoma nowThe forecast where you are
The other tornadoes of June 18, 2011
10 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| June 18 | 2:00 PM MDT | EF0 | Scotts Bluff, NE | 0.0 | 25 | |||
| June 18 | 3:52 PM MDT | EF0 | Cheyenne, CO | 0.3 | 10 | |||
| June 18 | 4:24 PM MDT | EF0 | Cheyenne, CO | 0.3 | 10 | |||
| June 18 | 7:40 PM CDT | EF0 | Gove, KS | 0.3 | 10 | |||
| June 18 | 8:09 PM CDT | EF0 | Osage, OK | 0.1 | 50 | |||
| June 18 | 8:10 PM CDT | EF0 | Osage, OK | 2.9 | 75 | |||
| June 18 | 9:13 PM CDT | EF0 | Washington, OK | 0.1 | 50 | |||
| June 18 | 11:35 PM CDT | EF1 | Dade, MO | 10.9 | 200 | |||
| June 18 | 11:40 PM CDT | EF1 | Dade, MO | 6.0 | 100 | $5,000 | ||
| June 18 | 12:03 AM CDT | EF0 | Greene, MO | 2.8 | 100 | $30,000 |
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.