EF1 tornado, Armstrong to Blooming Prairie, Minnesota, June 17, 2010

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.

Rating

EF1

Date

June 17, 2010

Touchdown

7:15 PM CDT (00:15 UTC)

Lifted

7:48 PM CDT (00:48 UTC)

On the ground

33 minutes

Path length

12.6 miles (20.3 km)

Path width

600 yards (549 m)

Deaths

0

Injuries

0

Counties

Freeborn and Steele counties

Touchdown point

43.763, -93.318

Lift-off point

43.930, -93.229

Record number

1006171815-01

Several strong storms developed in west-central Minnesota during the mid afternoon hours of June 17th. ||These storms quickly become severe and produced softball size hail northwest of Alexandria and a tornado near Leaf Valley that became the EF-4 that moved through Wadena, Minnesota. ||By the late afternoon, numerous thunderstorms developed across southern Minnesota along the leading edge of extreme instability. ||Numerous funnel cloud reports and a few brief tornado touchdowns were noted prior to 5 pm, but once the low level shear (0-1 km) increased significantly from 15 knots, to over 35 knots, strong tornadoes developed along the Iowa border.| |These storms along the Iowa border produced a series of long-lived tornadoes near Albert Lea, Minnesota. Very large hail also accompanied some tornadoes along with flash flooding.

This was a satellite tornado to the Conger EF-4. It damaged trees, several grain bins and structures.

This tornado touched down near the intersection of Interstate 35 and Freeborn County Road 31. Multiple outbuildings were destroyed and numerous large trees were broken or toppled. It exited Freeborn County just north of Geneva, where it continued into Steele County.

This tornado moved from Freeborn County and into Steele County and began moving to the north-northwest, thereby missing the city of Ellendale. At about (43.9255, -93.3453), it began moving toward the northwest, and at about (43.9407, -93.3627), it actually turned some more and moved toward the west-northwest until it finally dissipated. Accounting for the change in direction, the tornado had an actual path length of 7.7 miles in Steele County. Along the way, several homes experienced significant structural damage, with one house completely destroyed and the roof removed from two others. Many outbuildings were destroyed, and hundreds of trees were uprooted and snapped.

This tornado originated in Freeborn County, near Clark's Grove and producing minor damage in Geneva. It entered Steele County near County Road 45 and 168th Street SW and moved north-northeast for most of the time it existed, but at about (43.9154, -93.2159), it turned and began moving to the north-northwest, and dissipated while on its north-northwest track. Thus, the overall path length was 12.93 miles when accounting for the change in direction. In Steele County, several outbuildings were destroyed, the roof was taken off a barn, and numerous large trees were downed.

This tornado destroyed a barn, broke dozens of trees, and damaged a few sheds. As it began to dissipate, it became very narrow and then rotated halfway around a new tornado west of Hollandale. Video filmed by storm chaser.

A tornado developed just to the southeast of the intersection of County Roads 30 and 35, or about 1/4 mile southeast of where the Hollandale EF-3 had dissipated. This new tornado tracked northeast, hitting three farmsteads just east of the intersection of county roads 30 and 35. Numerous trees were snapped and a shed and other outbuildings were destroyed. For the latter portion of its track, the tornado moved through fields and groves, with more crop damage and broken trees. Photos and video recorded by storm chaser.

This EF-2 tornado touched down and tracked east-northeast, and soon crossed the path of the Blooming Prairie EF-3 that had moved north-northeast about 10 minutes earlier. A manufactured home was obliterated by the EF-2. A woman inside the home was blown about 20 feet, but was found under debris, rescued by law enforcement, and survived. The tornado continued moving east-northeast, and several outbuildings were destroyed, along with many broken trees. The tornado continued into Dodge County.

This tornado moved north-northeast and caused minor damage to outbuildings and broke several dozen trees. It exited Steele County about 3/4 mile south of Steele County Road 26 and continued into Dodge County.

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

31 minutes of warning. NWS MPX issued a tornado warning for this county at 23:44 UTC, 31 minutes before the tornado touched down, in force until 00:30 UTC.

The county was under a tornado watch, issued at 18:54 UTC and running to 02:00 UTC.

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 Storm Prediction Center had this point in a Moderate Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 20:06 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 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.

The Minneapolis radar (KMPX), 114 km away, was scanning. The volume nearest the touchdown began at 00:14 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.

Local storm reports within 60 km of the path, in the three hours either side.

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

The live radar over the trackEvery 2010 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

73 more were confirmed in the United States that day.

All 74 of them

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.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.