A strong upper level disturbance triggered strong and severe thunderstorms across much of northeast Minnesota during the morning and early afternoon hours.
By mid afternoon, very warm and moist air surged north ahead of low pressure over the Dakotas, while a cold front stretched across central Minnesota. This combination of meteorological conditions set the stage for additional severe thunderstorm development through the evening.
Storms developed in a broken line in western Minnesota by mid afternoon and propagated eastward through the late afternoon into the Brainerd Lakes region. By this time, a nearly solid line of thunderstorms extended from central Minnesota northward almost to the Canadian border. Many reports of wind damage and hail were noted with these storms as they moved east.
One particular area of wind damage was concentrated in northern Aitkin County, north of McGregor. Tree damage was widespread along a 6-mile path, from about 3 miles east of Palisade, to the south end of Big Sandy Lake. Results of a NWS storm survey assessment suggested that straight line and downburst winds were the primary cause. The majority of trees were blown down in one direction or fanned out in a divergent pattern. Many of the trees downed were over one foot in diameter, and some as large as two feet in diameter.
Thousands of trees in a 420 acre area of St. Croix State Park were mangled or uprooted. This area will be logged to mitigate wildfires.

Hail in CASS, MINNESOTA
From 11-JUL-08 16:55:00 to 11-JUL-08 16:55:00 (CST-6)
Location: GULL LAKE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in AITKIN, MINNESOTA
From 11-JUL-08 18:30:00 to 11-JUL-08 18:30:00 (CST-6)
Location: RUSH CITY MUNI ARPT
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous trees were blown down.

Thunderstorm Wind in AITKIN, MINNESOTA
From 11-JUL-08 18:10:00 to 11-JUL-08 18:10:00 (CST-6)
Location: PALISADE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Many trees were blown down along Highway 22.

Hail in CASS, MINNESOTA
From 11-JUL-08 16:55:00 to 11-JUL-08 16:55:00 (CST-6)
Location: PILLAGER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail fell for on-half hour.

Funnel Cloud in CASS, MINNESOTA
From 11-JUL-08 17:15:00 to 11-JUL-08 17:15:00 (CST-6)
Location: LEADER
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several funnel clouds were spotted, along with wind gusts of up to 70 mph.

Thunderstorm Wind in PINE, MINNESOTA
From 11-JUL-08 19:20:00 to 11-JUL-08 19:20:00 (CST-6)
Location: CLOVERDALE
Magnitude: 60.00 EG
Property damage: 0.00K
Reported by: Newspaper

Thousands of trees were mangled or uprooted on 420 acres of St. Croix State Park.

Hail in ST. LOUIS, MINNESOTA
From 11-JUL-08 09:50:00 to 11-JUL-08 09:50:00 (CST-6)
Location: KABETOGAMA
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Thunderstorm Wind in CASS, MINNESOTA
From 11-JUL-08 17:15:00 to 11-JUL-08 17:15:00 (CST-6)
Location: LEADER
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous trees were blown down.

Hail in ST. LOUIS, MINNESOTA
From 11-JUL-08 11:25:00 to 11-JUL-08 11:25:00 (CST-6)
Location: BUYCK
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in PINE, MINNESOTA
From 11-JUL-08 19:10:00 to 11-JUL-08 19:10:00 (CST-6)
Location: HINCKLEY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous trees were blown down.

Thunderstorm Wind in PINE, MINNESOTA
From 11-JUL-08 19:20:00 to 11-JUL-08 19:20:00 (CST-6)
Location: STURGEON LAKE
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several trees were blown down with considerable debris scattered across roadways.

Hail in CROW WING, MINNESOTA
From 11-JUL-08 17:05:00 to 11-JUL-08 17:05:00 (CST-6)
Location: NISSWA
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CROW WING, MINNESOTA
From 11-JUL-08 17:27:00 to 11-JUL-08 17:27:00 (CST-6)
Location: NISSWA
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Trees were blown down on Ojibwa Road.

Thunderstorm Wind in ITASCA, MINNESOTA
From 11-JUL-08 17:20:00 to 11-JUL-08 17:20:00 (CST-6)
Location: MAX
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous 15 to 20 inch diameter trees were blown down along County Highway 4.

Thunderstorm Wind in KOOCHICHING, MINNESOTA
From 11-JUL-08 09:05:00 to 11-JUL-08 09:05:00 (CST-6)
Location: RAY
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A roof was damaged along Highway 217 near mile post 17.

Thunderstorm Wind in KOOCHICHING, MINNESOTA
From 11-JUL-08 09:05:00 to 11-JUL-08 09:05:00 (CST-6)
Location: LITTLE FORK
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

An 18-inch spruce tree was snapped and a 30-inch oak tree was blown down. Several other trees were blown down.

Thunderstorm Wind in KOOCHICHING, MINNESOTA
From 11-JUL-08 09:04:00 to 11-JUL-08 09:04:00 (CST-6)
Location: LITTLE FORK
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Peak wind gust was reported at the Littlefork RAWS Station.

Thunderstorm Wind in KOOCHICHING, MINNESOTA
From 11-JUL-08 09:00:00 to 11-JUL-08 09:00:00 (CST-6)
Location: LITTLE FORK
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Twelve inch diameter trees were blown down across 2nd Street in Littlefork, along with damage to garages in town.

Hail in KOOCHICHING, MINNESOTA
From 11-JUL-08 06:30:00 to 11-JUL-08 06:30:00 (CST-6)
Location: BIG FALLS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter