Tornadoes · United States · Minnesota · 2011

EF0 tornado, Lexington to Andover, Minnesota, June 21, 2011

From Lexington to Andover, this EF0 tornado ran 6.1 miles across Anoka County on June 21, 2011, touching down at 3:12 PM CDT and reaching 75 yards wide. It killed nobody, and did $500,000 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.

  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 21, 2011
Touchdown
3:12 PM CDT (20:12 UTC)
Lifted
3:25 PM CDT (20:25 UTC)
On the ground
13 minutes
Path length
6.1 miles (9.9 km)
Path width
75 yards (69 m)
Deaths
0
Injuries
0
Property damage
$500,000
County
Anoka County
Touchdown point
45.136, -93.236
Lift-off point
45.204, -93.317
Record number
1106211412-01

What the Weather Service recorded

Strong to severe thunderstorms developed across eastern Minnesota during the early afternoon of Tuesday, June 21st. Modest instability and a highly sheared environment, led to several funnel cloud reports across southern Minnesota. One of these funnel clouds touched down on the north side of the metro and caused damage.

An EF-0 tornado touched down near the intersection of Highway 10 and Central Avenue in Blaine, then traveled approximately 6.1 miles northwest to one half mile northwest of the intersection of County Highway 14, and Hanson Boulevard in Coon Rapids. It had maximum wind speeds of 70 to 80 mph. Most of the damage was associated with trees and power lines blown down along the path length. Some damage occurred when trees fell on homes.

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. One was issued for the county at another hour that day.

The county was under a tornado watch, issued at 19:15 UTC and running to 02:00 UTC.

Issued (UTC)ExpiredProductOffice
19:15 UTC02:00 UTCTornado WatchMPX
20:13 UTC20:45 UTCTornado WarningMPX

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 19:57 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.

Minneapolis, MN (KMPX), 12:00Z

8.2 hours before the tornado, 44 km from the path. June 21, 2011.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2011-06-21Temperature 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 -77179, lifted condensation level 629 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Minneapolis, MN at 12:00Z on 2011-06-21The 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 316 square meters per square second, 0 to 6 km bulk shear 49 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
0 J/kg
Mixed-layer CIN
-77179 J/kg
Surface CAPE
12 J/kg
Mixed-layer LCL
629 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
316 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.1 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

3.8 hours after it, 44 km from the path. June 22, 2011.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2011-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 120 joules per kilogram, CIN -6, lifted condensation level 1101 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Minneapolis, MN at 00:00Z on 2011-06-22The 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 86 square meters per square second, 0 to 6 km bulk shear 37 knots.193958Sfc1 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
120 J/kg
Mixed-layer CIN
-6 J/kg
Surface CAPE
1200 J/kg
Mixed-layer LCL
1101 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

The radar

The Minneapolis radar (KMPX), 42 km away, was scanning. The volume nearest the touchdown began at 20:12 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
20:12 UTCTORNADO3 Sw BlaineAnoka, MNAN NWS STORM DAMAGE SURVEY TEAM DETERMINED AN EF-0 TORNADO TRACKED FROM NEAR THE INTERSECTION OF U.S. HIGHWAY 10 AND CENTRAL AVENUE IN BLAINE...TO THE NORTHWEST FOR APPROXIMATELY FIVE AND A HALF MILES...ENDING ONE HALF M
20:15 UTCTORNADOCoon RapidsAnoka, MNTORNADO REPORTED NEAR THE INTERSECTION OF HANSON AND MAIN ST. TREES AND POWER LINES DOWN IN COON RAPIDS.
20:17 UTCFUNNEL CLOUDBlaineAnoka, MNAT HWY 65 AND HWY 10.
20:29 UTCFUNNEL CLOUDAndoverAnoka, MNAT THE INTERSECTION OF BUNKER LAKE AND HANSON BLVD.
20:32 UTCTORNADOCoon RapidsAnoka, MNTORNADO REPORTED NEAR THE INTERSECTION OF HANSON AND MAINE.
21:08 UTCHEAVY RAIN 22 S HastyWright, MNREPORTED TO HAVE FALLEN IN 12 MINUTES.

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 June 21, 2011

9 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 211:15 AM CDTEF0Tama, IA0.830$75,000
June 213:21 PM CDTEF1Fond du Lac, WI2.6150$30,000
June 213:31 PM CDTEF1Green Lake, WI2.2150$5,000
June 213:36 PM CDTEF1Fond du Lac, WI0.9100$15,000
June 213:38 PM CDTEF1Green Lake, WI1.6100$2,000
June 213:55 PM CDTEF0Shelby, TX3.975
June 215:00 PM CDTEF0Shelby, TX1.675
June 218:31 PM CDTEF1DuPage, IL2.1200$500,000
June 218:48 PM CDTEF1Cook, IL2.4200$50,000

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.