Tornadoes · United States · Montana · 2012

EF0 tornado, Eagleton, Montana, June 5, 2012

This EF0 tornado ran 1.1 miles across Chouteau County on June 5, 2012, touching down at 7:10 PM MDT and reaching 100 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.

  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.

The record

Rating
EF0
Date
June 5, 2012
Touchdown
7:10 PM MDT (01:10 UTC)
Lifted
8:15 PM MDT (02:15 UTC)
On the ground
65 minutes
Path length
1.1 miles (1.7 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
County
Chouteau County
Touchdown point
48.039, -109.820
Lift-off point
48.053, -109.830
Record number
1206051910-01

The damage survey

2 damage points were recorded along this path by NWS TFX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0.

  • The area the tornado was reported was extensively rural. Tree damage was noted 16 miles southeast of Big Sandy in the Eagle Creek drainage.

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

Thunderstorms spawned three tornadoes and large hail over portions of North Central Montana during the late afternoon and early evening hours. Some structural damage was reported and surveyed.

The area the tornado was reported was extensively rural. Tree damage was noted 16 miles southeast of Big Sandy in the Eagle Creek drainage.

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

The warnings

18 minutes of warning. NWS TFX issued a tornado warning for this county at 00:52 UTC, 18 minutes before the tornado touched down, in force until 01:15 UTC.

The county was under a tornado watch, issued at 20:37 UTC and running to 05:00 UTC.

Issued (UTC)ExpiredProductOffice
20:37 UTC05:00 UTCTornado WatchTFX
00:11 UTC01:00 UTCTornado WarningTFX
00:16 UTC01:15 UTCSevere Thunderstorm WarningTFX
00:52 UTC01:15 UTCTornado WarningTFX
01:06 UTC01:30 UTCTornado WarningTFX
01:24 UTC02:15 UTCSevere Thunderstorm WarningTFX
01:29 UTC02:15 UTCTornado WarningTFX
02:09 UTC02:24 UTCTornado WarningTFX

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:36 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.

Great_falls, MT (KTFX), 12:00Z

10.8 hours after it, 87 km from the path. June 6, 2012.

Skew-T log-pSkew-T log-p diagram, Great_falls, MT at 12:00Z on 2012-06-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -77000, lifted condensation level 1157 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Great_falls, MT at 12:00Z on 2012-06-06The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity -48 square meters per square second, 0 to 6 km bulk shear 82 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-77000 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1157 m above ground
0-6 km bulk shear
82 kt
0-1 km bulk shear
4 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
-18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

The surface observations

Havre (HVR), 55 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
23:53 UTC855990° 14 kt997
00:53 UTC826140° 9 kt996.6
01:53 UTC806160° 17 kt994.9
02:53 UTC7861110° 13 kt20995.3

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

The radar

The Great Falls radar (KTFX), 134 km away, was scanning. The volume nearest the touchdown began at 01:10 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)ReportWhereCountyRemark
00:55 UTCHAIL 116 E GeraldineChouteau, MTESTIMATED 1.0 INCH PLUS SIZE HAIL
01:33 UTCTORNADO8 Se Big SandyChouteau, MTSPOTTER CONFIRMED CONE TORNADO APPROX 8 MILES SSE OF BIG SANDY
01:33 UTCTORNADOBig SandyChouteau, MTSPOTTER CONFIRMED CONE TORNADO
01:35 UTCHAIL 0.55 N LomaChouteau, MT
01:58 UTCHAIL 1.258 W Big SandyChouteau, MT

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

This ground now

The live radar over the trackEvery 2012 tornado in MontanaEvery tornado in Montana since 1950Warnings in force in Montana nowThe forecast where you are

The other tornadoes of June 5, 2012

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 53:40 PM MDTEF1Meagher, MT2.8300
June 56:41 PM MDTEF0Judith Basin, MT3.8400

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.