EF3 tornado, Capitol, Montana, June 17, 2014

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 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 mphthis tornado

   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

EF3

Date

June 17, 2014

Touchdown

2:27 PM MDT (20:27 UTC)

Lifted

3:30 PM MDT (21:30 UTC)

On the ground

63 minutes

Path length

10.0 miles (16.1 km)

Path width

880 yards (805 m)

Deaths

0

Injuries

0

County

Carter County

Touchdown point

45.478, -104.183

Lift-off point

45.568, -104.133

Record number

1406171427-01

A supercell thunderstorm produced a long-lived tornado across parts of East Central Carter County during the afternoon of June 17th. Eye-witnesses reported that the tornado was on the ground for approximately one hour.

A supercell thunderstorm developed very quickly in Eastern Carter County around 2:15 pm. The thunderstorm produced the first ever EF-3 rated tornado in southern Montana. The tornado first touched down at 2:27 pm around 13 miles southwest of Camp Crook, South Dakota, or about 10 miles southwest of Capitol, Montana. The tornado formed in the Sheep Mountains and eventually crossed Tie Creek Road as it moved slowly north. People lost site of the tornado as it entered Custer National Forest around 3:30 pm. ||The tornado was on the ground for an hour and traveled 10 miles and was reported to be a half mile wide at times. The tornado completely destroyed a trailer home, twisting and throwing debris over a mile. A small and old A-frame school house was completely destroyed, with debris blown 100 yards away, leaving only the basement behind. Six vehicles were picked up and tossed up to 200 yards. Around 20 power poles were snapped off with one pulled up out of the ground. In addition, 20 hay bales, weighing 3/4 ton a piece, were blown so far away that they were not recovered. A swath of trees on the north end of the track into the Custer National Forest was flattened by the tornado. There were no injuries or deaths from the tornado but two horses were killed. ||This was the strongest tornado ever recorded in the Billings National Weather Service area of responsibility.

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

12 minutes of warning. NWS BYZ issued a tornado warning for this county at 20:15 UTC, 12 minutes before the tornado touched down, in force until 21:00 UTC.

The county was under a tornado watch, issued at 18:33 UTC and running to 01:58 UTC.

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, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:44 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), 187 km away, was scanning. The volume nearest the touchdown began at 20:27 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 2014 tornado in MontanaEvery tornado in Montana since 1950Warnings in force in Montana nowThe forecast where you are

19 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.