The last night of the unusual prolonged heat wave brought another round of severe thunderstorms. Surface dew point temperatures continued in the oppressive 70F to 80F range. With the extreme heat, mid level temperatures also remained quite warm. However, the combination of a subtle upper level disturbance and a modest low level jet helped spawn the thunderstorms.

Thunderstorm Wind in POLK, MINNESOTA
From 20-JUL-11 06:10:00 to 20-JUL-11 06:10:00 (CST-6)
Location: NORTHLAND
Magnitude: 55.00 EG
Reported by: Law Enforcement

Several trees were uprooted and large tree branches were snapped off in farm yards and shelterbelts in central Higdem Township.

Thunderstorm Wind in KITTSON, MINNESOTA
From 20-JUL-11 06:11:00 to 20-JUL-11 06:11:00 (CST-6)
Location: DONALDSON
Magnitude: 55.00 EG
Reported by: NWS Storm Survey

A few trees were snapped in a shelterbelt south of highway 11.

Thunderstorm Wind in KITTSON, MINNESOTA
From 20-JUL-11 06:25:00 to 20-JUL-11 06:25:00 (CST-6)
Location: ENOK
Magnitude: 70.00 EG
Reported by: NWS Storm Survey

Numerous trees were snapped or uprooted in shelterbelts across much of Springbrook Township.

Thunderstorm Wind in KITTSON, MINNESOTA
From 20-JUL-11 06:38:00 to 20-JUL-11 06:38:00 (CST-6)
Location: HALMA
Magnitude: 52.00 EG
Reported by: Amateur Radio

A few large tree branches and limbs were broken down.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:10:00 to 20-JUL-11 07:10:00 (CST-6)
Location: GREENBUSH ARPT
Magnitude: 70.00 EG
Reported by: Trained Spotter

Several large cottonwood, poplar and boxelder trees were snapped or uprooted in a farm yard. Shingles were also torn off of roofs and flying tree branches were embedded in roofs.

Thunderstorm Wind in LAKE OF THE WOODS, MINNESOTA
From 20-JUL-11 08:35:00 to 20-JUL-11 08:45:00 (CST-6)
Location: LUDE
Magnitude: 55.00 EG
Reported by: Trained Spotter

Several large tree limbs were broken down around Oak Island.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 08:40:00 to 20-JUL-11 08:40:00 (CST-6)
Location: SWIFT
Magnitude: 60.00 EG
Reported by: Fire Department/Rescue

A large number of trees were severely damaged across northern Laona Township. Mature pine trees were snapped off midway up.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:40:00 to 20-JUL-11 07:40:00 (CST-6)
Location: WANNASKA
Magnitude: 60.00 EG
Reported by: Public

Large trees, greater than a foot in diameter, were blown down.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:25:00 to 20-JUL-11 07:25:00 (CST-6)
Location: ROSEAU
Magnitude: 56.00 EG
Reported by: Trained Spotter

Many 6 to 8 inch diameter trees were blown down in town.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:45:00 to 20-JUL-11 07:45:00 (CST-6)
Location: ROSEAU
Magnitude: 52.00 EG
Reported by: Trained Spotter

Dime sized hail accompanied the strong wind.

Thunderstorm Wind in MARSHALL, MINNESOTA
From 20-JUL-11 06:22:00 to 20-JUL-11 06:22:00 (CST-6)
Location: STEPHEN
Magnitude: 52.00 EG
Reported by: Public

Strong wind gusts were reported.

Thunderstorm Wind in MARSHALL, MINNESOTA
From 20-JUL-11 06:27:00 to 20-JUL-11 06:27:00 (CST-6)
Location: ENGLUND
Magnitude: 68.00 MG
Reported by: Mesonet

The wind gust was measured by the Stephen NDAWN.

Thunderstorm Wind in MARSHALL, MINNESOTA
From 20-JUL-11 06:30:00 to 20-JUL-11 06:30:00 (CST-6)
Location: FLORIAN
Magnitude: 60.00 EG
Reported by: Public

A large tree was blown down.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 06:58:00 to 20-JUL-11 06:58:00 (CST-6)
Location: PELAN
Magnitude: 65.00 MG
Reported by: Mesonet

The wind gust was measured by the NDAWN 7 miles west of Greenbush.

Thunderstorm Wind in KITTSON, MINNESOTA
From 20-JUL-11 06:35:00 to 20-JUL-11 06:35:00 (CST-6)
Location: KARLSTAD
Magnitude: 83.00 EG
Property damage: 600.00K
Crop damage: 200.00K
Reported by: NWS Storm Survey

The county highway department building was severely damaged. Equipment in the building was also damaged. Peak winds were estimated at 95 mph based on extreme structural damage and related tree damage. Trees and power lines were down all around Karlstad.

Thunderstorm Wind in KITTSON, MINNESOTA
From 20-JUL-11 06:35:00 to 20-JUL-11 06:35:00 (CST-6)
Location: KARLSTAD
Magnitude: 83.00 EG
Property damage: 200.00K
Crop damage: 250.00K
Reported by: NWS Storm Survey

Widespread wind damage was noted across Deerwood and Arveson townships. Numerous large tree limbs were broken down in yards, shelterbelts, and groves. Peak winds were estimated at 85 to 95 mph.

Lightning in ROSEAU, MINNESOTA
From 20-JUL-11 08:10:00 to 20-JUL-11 08:10:00 (CST-6)
Location: MALUNG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A fire was started by a lightning strike.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:20:00 to 20-JUL-11 07:20:00 (CST-6)
Location: HOMOLKA
Magnitude: 60.00 EG
Property damage: 5.00K
Crop damage: 200.00K
Reported by: Law Enforcement

The roof was ripped off of a 180 foot long hay shed. Numerous tree limbs were broken down in farmsteads across Nereson Township.

Thunderstorm Wind in MARSHALL, MINNESOTA
From 20-JUL-11 06:40:00 to 20-JUL-11 06:40:00 (CST-6)
Location: STRANDQUIST
Magnitude: 83.00 EG
Property damage: 40.00K
Crop damage: 250.00K
Reported by: NWS Storm Survey

Three wooden power poles were snapped along highway 59. Numerous nearby poplar trees were also snapped.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:05:00 to 20-JUL-11 07:05:00 (CST-6)
Location: GREENBUSH
Magnitude: 78.00 EG
Property damage: 700.00K
Crop damage: 300.00K
Reported by: Amateur Radio

Numerous large tree limbs were broken down around Greenbush. Trees were blown down on cars and roofs of homes. Power lines were also downed. Large commercial scale steel grain bins were dented or collapsed inward at the elevator complex. Smaller farm scale steel bins nearby were torn from their foundations and rolled.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:10:00 to 20-JUL-11 07:10:00 (CST-6)
Location: BADGER
Magnitude: 63.00 EG
Property damage: 50.00K
Crop damage: 100.00K
Reported by: Trained Spotter

Several large three foot diameter trees were broken down in Badger. A wooden storage shed at the cemetery was torn off its foundation and flipped over.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 06:48:00 to 20-JUL-11 06:48:00 (CST-6)
Location: GREENBUSH ARPT
Magnitude: 70.00 EG
Reported by: COOP Observer

Three steel grain bins were dented and tin roofing was torn off a pole shed. Across the highway and south of this location, another pole shed had a steel door and a steel corner panel torn off.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:10:00 to 20-JUL-11 07:10:00 (CST-6)
Location: FOX
Magnitude: 61.00 EG
Reported by: Law Enforcement

The strong winds were reported by law enforcement personnel.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:15:00 to 20-JUL-11 07:15:00 (CST-6)
Location: ROSEAU
Magnitude: 50.00 EG
Reported by: Trained Spotter

Numerous four inch diameter tree branches were blown down.

Thunderstorm Wind in ROSEAU, MINNESOTA
From 20-JUL-11 07:34:00 to 20-JUL-11 07:34:00 (CST-6)
Location: BADGER
Magnitude: 55.00 EG
Reported by: Public

A second wave of thunderstorm winds broke down numerous additional four to six inch diameter tree limbs.

Thunderstorm Wind in MARSHALL, MINNESOTA
From 20-JUL-11 06:40:00 to 20-JUL-11 06:40:00 (CST-6)
Location: FLORIAN
Magnitude: 65.00 EG
Property damage: 20.00K
Crop damage: 100.00K
Reported by: Trained Spotter

A grain bin was tipped over.