EF1 tornado, Douglas to Rochester, 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

9:03 PM CDT (02:03 UTC)

Lifted

9:10 PM CDT (02:10 UTC)

On the ground

7 minutes

Path length

2.4 miles (3.8 km)

Path width

150 yards (137 m)

Deaths

0

Injuries

0

Property damage

$1.9 million

County

Olmsted County

Touchdown point

44.065, -92.540

Lift-off point

44.080, -92.497

Record number

1006172003-01

Severe thunderstorms developed during the evening of June 17th along a warm front that was lifting north through southern Minnesota and northeast Iowa. These severe thunderstorms produced the first tornadoes of 2010 for southeast Minnesota with three confirmed tornadoes. Two of these occurred in rural portions of Dodge County while the third moved through the northwest side of Rochester (Olmsted County). The tornadoes in Dodge County were rated EF0 and EF1 on the Enhanced Fujita Scale while the tornado in Rochester was rated EF1. The tornado in Rochester was the first to occur within the city limits since August 1995. As the storms progressed east, they became prolific wind producers with wind gusts of 60 to 80 mph across Olmsted and Winona Counties. Numerous buildings were damaged or destroyed with most of this occurring from Rochester east through the Winona area (Winona County). Federal Disaster Declarations for public assistance were designated for Olmsted and Houston Counties in southeast Minnesota.

An EF1 tornado produced intermittent damage starting near 50th Ave NW just south of the Northern Hills Golf Course northeast almost to the intersection of 55th St NW and and 23rd Ave NW in the city of Rochester. The path of the tornado took it through a residential area where several homes were damaged. It also struck a Menards store doing extensive damage before dissipating a few minutes later. According to media reports, the tornado damaged at least 30 homes, one of which was destroyed.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

The county was under a tornado watch, issued at 22:50 UTC and running to 04:24 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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 00:53 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 La Crosse radar (KARX), 110 km away, was scanning. The volume nearest the touchdown began at 02:03 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.