Tornadoes · United States · Minnesota · 2011

EF1 tornado, Espelie, Minnesota, July 24, 2011

This EF1 tornado ran 2.5 miles across Marshall County on July 24, 2011, touching down at 7:12 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.

  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
July 24, 2011
Touchdown
7:12 PM CDT (00:12 UTC)
Lifted
7:17 PM CDT (00:17 UTC)
On the ground
5 minutes
Path length
2.5 miles (4.0 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
County
Marshall County
Touchdown point
48.260, -95.800
Lift-off point
48.208, -95.760
Record number
1107241812-01

What the Weather Service recorded

Despite the fact there was very little surface forcing, severe thunderstorms fired up across northeast North Dakota and northwest Minnesota on the evening of the 24th. A weak surface trough did extend from near Bismarck (ND) into the extreme northwest corner of Minnesota. Most of the thunderstorm activity was diurnally driven and associated with good upper jet support. Therefore most of the thunderstorms flared up in the very late afternoon and diminished around sunset.

This tornado was briefly viewed by spotters near Goodridge. A 10 inch diameter ash tree was snapped about four feet above the ground. Several sections of tin roofing were torn off of a house and numerous large tree branches were blown down in shelterbelts and groves. Peak winds were estimated at 90 mph.

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

The warnings

13 minutes of warning. NWS FGF issued a tornado warning for this county at 23:59 UTC, 13 minutes before the tornado touched down, in force until 00:45 UTC.

Issued (UTC)ExpiredProductOffice
23:23 UTC00:30 UTCSevere Thunderstorm WarningFGF
23:46 UTC00:45 UTCSevere Thunderstorm WarningFGF
23:59 UTC00:45 UTCTornado WarningFGF
00:08 UTC00:45 UTCTornado WarningFGF

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 19:26 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

0.2 hours before the tornado, 187 km from the path. July 25, 2011.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 00:00Z on 2011-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 99 joules per kilogram, CIN -6, lifted condensation level 1295 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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 2011-07-25The 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 56 square meters per square second, 0 to 6 km bulk shear 42 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
99 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
399 J/kg
Mixed-layer LCL
1295 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
56 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2
0-3 km lapse rate
7.5 K/km

Open this sounding in Storm Lab

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

11.8 hours after it, 187 km from the path. July 25, 2011.

Skew-T log-pSkew-T log-p diagram, International Fa, MN at 12:00Z on 2011-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 26 joules per kilogram, CIN -86, lifted condensation level 1593 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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 2011-07-25The 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 176 square meters per square second, 0 to 6 km bulk shear 59 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
26 J/kg
Mixed-layer CIN
-86 J/kg
Surface CAPE
509 J/kg
Mixed-layer LCL
1593 m above ground
0-6 km bulk shear
59 kt
0-1 km bulk shear
30 kt
0-1 km storm-relative helicity
176 m²/s²
0-3 km storm-relative helicity
209 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.3
0-3 km lapse rate
5.8 K/km

Open this sounding in Storm Lab

The surface observations

Thief River (TVF), 35 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
22:55 UTC75.262.6220° 11 kt1016.6
23:15 UTC75.262.6200° 8 kt1016.3
23:35 UTC75.262.6210° 16 kt201016.3
23:55 UTC75.262.6210° 12 kt201016.3
00:15 UTC73.462.6210° 10 kt1016.3
00:35 UTC73.464.4200° 7 kt1016.3
00:55 UTC73.464.4220° 11 kt141015.9
01:15 UTC71.662.6240° 11 kt211015.6
01:35 UTC71.664.4240° 8 kt1015.9
01:55 UTC69.862.6270° 6 kt1016.3
02:15 UTC69.862.6270° 6 kt1016.6
02:35 UTC69.862.6230° 4 kt1016.6

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

The radar

The Fargo/Grand Forks radar (KMVX), 139 km away, was scanning. The volume nearest the touchdown began at 00:13 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
00:15 UTCTSTM WND DMG7 Ne GoodridgeMarshall, MNTIN BLOWN OFF OF ROOF. 8 TO 10 INCH DIAMETER TREE BRANCHES DOWN.
00:15 UTCHAIL 1.757 Ne GoodridgeMarshall, MN
02:12 UTCTSTM WND DMG4 N McintoshPolk, MNHALF A PINE TREE DOWN AT ST JOHNS CEMETARY...OTHER LARGE BRANCHES DOWN BLOCKING ROAD.

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 MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of July 24, 2011

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 247:42 PM CDTEF0Marshall, MN0.110
July 246:50 PM MDTEF0Navajo, AZ1.010
July 248:51 PM EDTEF0Midland, MI0.350

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.