Tornadoes · United States · Minnesota · 2001
F2 tornado, Glenville to Oakland, Minnesota, May 1, 2001
From Glenville to Oakland, this F2 tornado ran 5.0 miles across Freeborn County on May 1, 2001, touching down at 7:15 PM CDT and reaching 250 yards wide. It killed nobody, and did $2.0 million of property damage.
The rating scale
Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.
F040 to 72 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
F2113 to 157 mphthis tornado
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.
F3158 to 206 mph
Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
F5261 to 318 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
- F2
- Date
- May 1, 2001
- Touchdown
- 7:15 PM CDT (00:15 UTC)
- Path length
- 5.0 miles (8.0 km)
- Path width
- 250 yards (229 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $2.0 million
- County
- Freeborn County
- Touchdown point
- 43.650, -93.130
- Lift-off point
- 43.670, -93.050
- Record number
- 862
What the Weather Service recorded
Tornado first touched down on the western fringe of Glenville, and produced major damage, especially on the northwest side of Glenville. There were 25 homes that sustained major damage, and 70 with minor damage. Damage survey indicated F2 damage on northwest side of Glenville, with F1 damage along rest of path.
Shortly after the Glenville tornado dissipated, another tornado formed 4 miles southwest of Oakland and dissipated about 1/2 mile before it would have crossed Interstate 90, which law enforcement had barricaded. Major damage to 3 farmsteads, minor damage to 8 others per damage survey.
The third tornado in a series (the first one started at Glenville) formed just north of Interstate 90 and east of Oakland. It was on the ground for one mile in Freeborn County before crossing into Mower County, where it dissipated 4 N Austin (see Storm Data for southeast Minnesota). A few grain bins were blown down.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
9 minutes of warning. NWS MPX issued a tornado warning for this county at 00:06 UTC, 9 minutes before the tornado touched down, in force until 00:30 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 22:18 UTC | 23:00 UTC | Severe Thunderstorm Warning | MPX |
| 00:05 UTC | 00:45 UTC | Severe Thunderstorm Warning | MPX |
| 00:06 UTC | 00:30 UTC | Tornado Warning | MPX |
| 00:30 UTC | 01:00 UTC | Tornado Warning | MPX |
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 Moderate Risk. The outlook in force was issued at 21:05 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), 00:00Z
0.3 hours before the tornado, 138 km from the path. May 2, 2001.
- Mixed-layer CAPE
- 453 J/kg
- Mixed-layer CIN
- -52 J/kg
- Surface CAPE
- 3841 J/kg
- Mixed-layer LCL
- 1677 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- -70 m²/s²
- 0-3 km storm-relative helicity
- 169 m²/s²
- Significant tornado parameter
- -0.0
- Supercell composite
- -4.0
- 0-3 km lapse rate
- 7.1 K/km
Minneapolis, MN (KMPX), 12:00Z
11.7 hours after it, 138 km from the path. May 2, 2001.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -80540 J/kg
- Surface CAPE
- 0 J/kg
- Mixed-layer LCL
- 1456 m above ground
- 0-6 km bulk shear
- 67 kt
- 0-1 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -26 m²/s²
- 0-3 km storm-relative helicity
- 49 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 5.2 K/km
The surface observations
Austin Municipal (AUM), 13 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 22:39 UTC | 77 | 62.6 | 180° 15 kt | 22 | 1002 | |
| 23:01 UTC | 75.2 | 62.6 | 180° 19 kt | 29 | 1001.7 | TS |
| 23:16 UTC | 75.2 | 62.6 | 170° 13 kt | 24 | 1002 | -VCTSRA |
| 23:38 UTC | 73.4 | 62.6 | 180° 16 kt | 21 | 1001.4 | -VCTSRA |
| 23:56 UTC | 73.4 | 62.6 | 200° 17 kt | 22 | 1002.7 | -TSRA |
| 00:18 UTC | 71.6 | 62.6 | 200° 21 kt | 28 | 1002.4 | +TSRA |
| 00:38 UTC | 64.4 | 57.2 | 230° 14 kt | 27 | 1002.7 | TSRA |
| 01:02 UTC | 68 | 60.8 | 230° 12 kt | 17 | 1003 | -TSRA |
| 01:16 UTC | 66.2 | 60.8 | 240° 16 kt | 28 | 1003.7 | -RA |
| 01:36 UTC | 69.8 | 60.8 | 250° 13 kt | 1004.1 | ||
| 01:56 UTC | 71.6 | 60.8 | 270° 9 kt | 1004.7 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Minneapolis radar (KMPX), 138 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.
This ground now
The live radar over the trackEvery 2001 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are
The other tornadoes of May 1, 2001
9 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 1 | 4:55 PM CDT | F0 | Blue Earth, MN | 0.1 | 25 | |||
| May 1 | 6:15 PM CDT | F0 | Burnett, WI | 1.5 | 50 | |||
| May 1 | 6:32 PM CDT | F0 | Steele, MN | 0.1 | 25 | |||
| May 1 | 6:58 PM CDT | F0 | Pierce, WI | 0.1 | 25 | |||
| May 1 | 7:02 PM CDT | F2 | Freeborn, MN | 7.0 | 440 | $20 million | ||
| May 1 | 7:29 PM CDT | F1 | Freeborn, MN | 6.0 | 250 | $200,000 | ||
| May 1 | 7:52 PM CDT | F0 | Mower, MN | 0.3 | 50 | |||
| May 1 | 8:06 PM CDT | F0 | Olmsted, MN | 0.2 | 50 | |||
| May 1 | 9:55 PM CDT | F1 | Oneida, WI | 1.5 | 125 | $10,000 |
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.