An area of low pressure working across the Upper Midwest on the 10th was able to pull abnormally high moisture into the region leading to sufficient instability for the development of storms. An upper jet was also over the area contributing to higher than normal amounts of shear as well resulting in some of the storms becoming severe across the region. Isolated reports of large hail and damaging winds were received along the North Shore of Lake Superior along with a rare October tornado that developed over the Boundary Waters Canoe Area Wilderness and tracked northward into Canada.

Hail in COOK, MINNESOTA
From 10-OCT-21 16:41:00 to 10-OCT-21 16:43:00 (CST-6)
Location: MARAIS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A search and rescue crew in the area had to take cover near Eagle Mountain due to the large hail.

Thunderstorm Wind in COOK, MINNESOTA
From 10-OCT-21 16:37:00 to 10-OCT-21 16:39:00 (CST-6)
Location: MARAIS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Multiple trees were down along Ball Club Road from the storm.

Thunderstorm Wind in COOK, MINNESOTA
From 10-OCT-21 16:29:00 to 10-OCT-21 16:31:00 (CST-6)
Location: MARAIS
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Multiple trees were downed along County Highway 57 on the north side of Devil Track Lake by the storm.

Tornado in COOK, MINNESOTA
From 10-OCT-21 17:10:00 to 10-OCT-21 17:20:00 (CST-6)
Location: HOVLAND
Tornado F-scale: EF2
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A rare late-season strong tornado caused tree damage
across parts of the Boundary Waters Canoe Area Wilderness in
northern Cook County. The tornado appeared to begin on Alder Lake,
initially causing damage near Campsite #3 where a small swath of
trees were downed, several snapped halfway down their trunks. The
tornado then traveled north causing sporadic damage until just north
of Rocky Lake where there was a more concentrated area of downed
trees roughly 270 yards across. Sporadic tree damage continued until
reaching Clearwater Lake and crossing the lake just west of Campsite
#5, causing significant damage north of Clearwater Lake and north to
the International Border (Mountain Lake). Significant tree damage was
observed along the Border Route Trail, of which passage was made
impossible as the tornado reached its maximum width of around 500
yards as it moved across the trail. Numerous trees were snapped near
their bases within this area of damage. The coverage of damage was
widespread with satellite imagery depicting over 80% of trees
uprooted, bent, or snapped across its path near the Border Route
Trail. The tornado then crossed the International Border and continued into Northwestern Ontario, Canada. No private property was damaged along the course of the tornado.
The National Weather Service appreciates the public reports, photos,
and videos of this tornado damage, aerial photographs from the US
Forest Service, and satellite imagery shared by the Northern
Tornadoes Project (Western University in Canada) which all aided in
an accurate assessment of the damage.

Thunderstorm Wind in ST. LOUIS, MINNESOTA
From 10-OCT-21 14:43:00 to 10-OCT-21 14:45:00 (CST-6)
Location: KABETOGAMA
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: State Official

A tree was downed onto a power line near the Kabetogama Visitor Center during the storm.