Tornadoes · United States · Minnesota · 2015

EF1 tornado, Mahnomen, Minnesota, June 22, 2015

This EF1 tornado ran 0.2 miles across Mahnomen County on June 22, 2015, touching down at 2:26 AM CDT and reaching 30 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 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.

The record

Rating
EF1
Date
June 22, 2015
Touchdown
2:26 AM CDT (07:26 UTC)
Lifted
2:27 AM CDT (07:27 UTC)
On the ground
1 minutes
Path length
0.2 miles (0.4 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Mahnomen County
Touchdown point
47.300, -95.970
Lift-off point
47.300, -95.970
Record number
1506220126-01

What the Weather Service recorded

A line of showers and thunderstorms tracked from central North Dakota into portions of northwest Minnesota, with the strongest storms traveling along the highway 200 corridor. There were several bowing segments which produced strong winds and a tornado.

A tornado tracked across southern portions of the city of Mahnomen, where it ripped roofing off of a maintenance shed, lifted and tipped a parked semi trailer, slid parked vehicles, and destroyed a small wooden shed. Flying debris impacted and damaged additional vehicles and structures near the casino. Peak wind speeds were estimated at 95 mph.

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.

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 General Thunderstorms Risk. The outlook in force was issued at 05:58 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.

International Fa, MN (KINL), 00:00Z

7.4 hours before the tornado, 244 km from the path. June 22, 2015.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 00:00Z on 2015-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 49 joules per kilogram, CIN -6, lifted condensation level 1907 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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, International Fa, MN at 00:00Z on 2015-06-22The 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 55 square meters per square second, 0 to 6 km bulk shear 29 knots.19395878Sfc1 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
49 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
517 J/kg
Mixed-layer LCL
1907 m above ground
0-6 km bulk shear
29 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
8.2 K/km

Open this sounding in Storm Lab

International Fa, MN (KINL), 12:00Z

4.6 hours after it, 244 km from the path. June 22, 2015.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 12:00Z on 2015-06-22Temperature 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 -79598, lifted condensation level 1664 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, International Fa, MN at 12:00Z on 2015-06-22The 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 -31 square meters per square second, 0 to 6 km bulk shear 38 knots.1939587897117Sfc1 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
-79598 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1664 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
3 kt
0-1 km storm-relative helicity
-31 m²/s²
0-3 km storm-relative helicity
-20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

The radar

The Fargo/Grand Forks radar (KMVX), 105 km away, was scanning. The volume nearest the touchdown began at 07:26 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
07:00 UTCTSTM WND DMGMahnomenMahnomen, MNSTRONG WIND GUST TIPPED OVER A SEMI TRUCK AND CAUSED DAMAGE TO CASINO BUILDING.
07:26 UTCTORNADO 11 S MahnomenMahnomen, MNA TORNADO TRACKED ACROSS FAR SOUTHERN MAHNOMEN FOR ROUGHLY 400 YARDS OVER A 30 TO 40 SECOND PERIOD. THIS TORNADO RIPPED ROOFING OFF OF A MAINTENANCE SHED... LIFTED AND TIPPED A PARKED SEMI TRAILER...SLID PARKED VEHICLES.

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

This ground now

The live radar over the trackEvery 2015 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of June 22, 2015

26 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 226:50 AM CDTEF0Nicollet, MN2.850
June 228:21 AM CDTEF1Fayette, IA1.5502$100,000
June 228:50 AM CDTEF0Crawford, WI1.335$10,000
June 229:06 AM CDTEF0Crawford, WI7.460$34,000
June 222:30 PM EDTEF1Ionia, MI4.61005$3.2 million
June 225:05 PM CDTEF3Marion, IA11.1575$150,000
June 225:50 PM CDTEF2Monroe, IA1.7290$125,000
June 227:14 PM EDTEF0Charlotte, FL0.615
June 227:08 PM CDTEF0Gray, KS0.650
June 227:14 PM CDTEF1Whiteside, IL2.275
June 227:15 PM CDTEF2Rock Island, IL4.2440
June 227:16 PM CDTEF0Whiteside, IL2.650
June 227:16 PM CDTEF1Whiteside, IL1.750
June 227:28 PM CDTEF1Lee, IL7.450
June 227:53 PM CDTEF2Lee, IL7.88807$1.0 million
June 228:19 PM CDTEF1LaSalle, IL1.5150$100,000
June 228:50 PM CDTEF1LaSalle, IL6.0150$100,000
June 2210:00 PM EDTEF2Saginaw, MI11.32502$600,000
June 2210:07 PM EDTEF1Tuscola, MI22.9250$501,000
June 229:17 PM CDTEF1Grundy, IL7.0150$50,000
June 229:43 PM CDTEF1Grundy, IL0.8100$50,000
June 229:45 PM CDTEF3Grundy, IL16.31,3207$25 million
June 2210:08 PM CDTEF1Kankakee, IL2.2300
June 2211:55 PM EDTEF0Saint Clair, MI0.650$10,000
June 2211:46 PM CDTEF0Kankakee, IL1.050
June 221:31 AM EDTEF1Washtenaw, MI4.3100$300,000

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.