Tornadoes · United States · Minnesota · 2009

EF0 tornado, Easton, Minnesota, June 21, 2009

Name: EF0 tornado, Easton, Minnesota, June 21, 2009
Start: 2009-06-22T00:36:00.000Z
Location: Easton, Minnesota

This EF0 tornado ran 0.0 miles across Faribault County on June 21, 2009, touching down at 7:36 PM CDT and reaching 5 yards wide. It killed nobody, and did $1,000 of property damage.

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 21, 2009
Touchdown: 7:36 PM CDT (00:36 UTC)
Path length: 0.0 miles (0.1 km)
Path width: 5 yards (5 m)
Deaths: 0
Injuries: 0
Property damage: $1,000
County: Faribault County
Touchdown point: 43.792, -93.906
Lift-off point: 43.792, -93.906
Record number: 0906211836-01

What the Weather Service recorded

Atmospheric conditions for tornadoes developed rapidly in far south central Minnesota the evening of June 21st. During the late afternoon, a very warm and humid air mass lifted northward across northern Iowa, and into far southern Minnesota. Several weak storms formed in northwest and north central Iowa and moved into south central Minnesota where a warm front laid. Winds shifted from the south to the east and southeast across Freeborn and Faribault counties of far south central Minnesota. The combination of increasing wind shear near the boundary layer, and enough lift from thunderstorms, brief tornadoes developed.

A tree was downed and a garage door damaged from a brief tornado at a farmstead. Rear flank downdraft winds also caused tree damage about 150 yards north-northwest of the tornado.

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

What forecasters said that day

The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Twin Cities, MN wrote its last area forecast discussion before the tornado touched down at Jun 21, 6:51 PM CDT, 45 minutes earlier.

Area forecast discussion, Jun 21, 6:51 PM CDT, 45 minutes before

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Hazardous weather outlook, Jun 21, 1:04 PM CDT, 6 hours 32 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
104 PM CDT SUN JUN 21 2009

MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028-
221100-
DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS-
BENTON-SHERBURNE-ISANTI-CHISAGO-LAC QUI PARLE-SWIFT-CHIPPEWA-
KANDIYOHI-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON-
YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA-
REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE-WATONWAN-BLUE EARTH-
WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN-POLK-BARRON-RUSK-
ST. CROIX-PIERCE-DUNN-PEPIN-EAU CLAIRE-
104 PM CDT SUN JUN 21 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTHERN MINNESOTA...AND WEST CENTRAL WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A CHANCE OF ISOLATED STRONG TO SEVERE THUNDERSTORMS OVER
PARTS OF SOUTH CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN THIS
AFTERNOON AND EVENING. THE PRIMARY THREAT AREA WOULD BE GENERALLY
SOUTH OF A LINE FROM REDWOOD FALLS...TO MANKATO...TO EAU
CLAIRE. THE MAIN THREATS ARE LARGE HAIL AND HEAVY RAIN. TORNADOES
ARE ALSO POSSIBLE OVER FAR SOUTH CENTRAL MINNESOTA LATER THIS
AFTERNOON AND EARLY EVENING...IF THE ATMOSPHERE HAS ENOUGH TIME TO
DESTABILIZE BEFORE SUNSET.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WORK WEEK. AT THIS
TIME...THERE IS A SMALL CHANCE FOR SOME OF THESE THUNDERSTORMS TO
BECOME SEVERE...MAINLY ON TUESDAY EVENING AND NIGHT.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON AND
EVENING OVER PARTS OF SOUTH CENTRAL MINNESOTA.

In the hours before

Special weather statement, Jun 21, 6:48 PM CDT, 48 minutes before

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Special weather statement, Jun 21, 6:51 PM CDT, 45 minutes before

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Local storm report, Jun 21, 7:05 PM CDT, 31 minutes before

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Special weather statement, Jun 21, 7:15 PM CDT, 21 minutes before

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Local storm report, Jun 21, 7:36 PM CDT, 0 minutes before

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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.

Minneapolis, MN (KMPX), 00:00Z

0.6 hours before the tornado, 120 km from the path. June 22, 2009.

Skew-T log-p

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.

Hodograph

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: 278 J/kg
Mixed-layer CIN: -57 J/kg
Surface CAPE: 273 J/kg
Mixed-layer LCL: 487 m above ground
0-6 km bulk shear: 37 kt
0-1 km bulk shear: 26 kt
0-1 km storm-relative helicity: 270 m²/s²
0-3 km storm-relative helicity: 347 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 3.9
0-3 km lapse rate: 5.2 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 12:00Z

11.4 hours after it, 120 km from the path. June 22, 2009.

Skew-T log-p

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.

Hodograph

Mixed-layer CAPE: 554 J/kg
Mixed-layer CIN: -135 J/kg
Surface CAPE: 700 J/kg
Mixed-layer LCL: 761 m above ground
0-6 km bulk shear: 29 kt
0-1 km bulk shear: 25 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6
0-3 km lapse rate: 4.3 K/km

Open this sounding in Storm Lab

The surface observations

Waseca (Awos) (ACQ), 42 km from the path, in the two hours either side.

Time (UTC)	Temp (°F)	Dew point (°F)	Wind	Gust (kt)	Pressure (mb)	Weather
00:00 UTC

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

The radar

The Minneapolis radar (KMPX), 121 km away, was scanning. The volume nearest the touchdown began at 00:34 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.

This ground now

The live radar over the track Every 2009 tornado in Minnesota Every tornado in Minnesota since 1950 Warnings in force in Minnesota now The forecast where you are

The other tornadoes of June 21, 2009

13 more were confirmed in the United States that day.

Date	Time	Rating	Where	Path (mi)	Width (yd)	Damage
June 21	11:50 AM MDT	EF0	Owyhee, ID	0.1	20
June 21	4:48 PM CDT	EF0	Hamilton, IA	1.4	30
June 21	5:29 PM CDT	EF0	Lyon, IA	0.4	50
June 21	5:36 PM CDT	EF0	Hamilton, IA	0.5	30
June 21	6:15 PM CDT	EF0	Hardin, IA	0.7	30
June 21	6:39 PM CDT	EF0	Hardin, IA	0.4	30
June 21	6:51 PM CDT	EF0	Grundy, IA	0.4	30
June 21	6:59 PM CDT	EF0	Hardin, IA	0.6	30
June 21	7:20 PM CDT	EF1	Grundy, IA	2.3	90	$25,000
June 21	7:25 PM CDT	EF1	Grundy, IA	2.1	70	$10,000
June 21	8:08 PM CDT	EF0	Faribault, MN	0.3	5	$1,000
June 21	8:18 PM CDT	EF0	Faribault, MN	0.0	5
June 21	8:32 PM CDT	EF0	Freeborn, MN	1.8	10

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.