119
NOUS43 KDLH 201836
PNSDLH
MNZ010>012-018>021-025-026-033>038-WIZ001>004-006>009-210645-

Public Information Statement
National Weather Service Duluth MN
136 PM CDT Fri Sep 20 2024

...NWS Damage Survey for 9/19/24 Tornado Event...

.Overview...

A cold front moved through north-central Minnesota in the late
afternoon hours on Thursday, September 20, 2024. Out ahead of the
cold front in northeast Minnesota, discrete severe thunderstorms
began to form in far northeast Minnesota along the US Hwy 53
corridor around 4 PM CT. The first Severe Thunderstorm Warning was
issued at 4:15 PM for parts of far northeast St. Louis County and
northwest Lake County as the severe storm moved northeastward
around 30 mph. By 4:55 PM, conditions within a different severe
supercell thunderstorm warranted the first Tornado Warning of the
evening to be issued for central St. Louis County around the
communities of Cotton and Canyon, MN. Between 5 and 5:30 PM that
evening, multiple additional Severe Thunderstorm and Tornado
Warnings were issued along and east of US Hwy 53 and along the
I-35 corridor into east- central Minnesota. The cold front
continued to move eastward through the early evening hours on the
20th, with storms beginning to enter Douglas and Burnett Counties
in northwest Wisconsin towards 6 PM as low-level funnel clouds
were reported by law enforcement and trained weather spotters.
Hail up to 1.5 inches in diameter was reported from the strongest
thunderstorms, but in very localized reports. As the air mass
began to cool and stabilized in the mid-evening hours, the threat
for additional tornadoes began to wane and the strongest
thunderstorms were limited to the Twin Ports and across northwest
Wisconsin. As the cold front entered northwest Wisconsin by late
evening, activity subsided to only showers and general
thunderstorms with no additional impacts reported overnight. In
total, 8 Tornado Warnings, 9 Severe Thunderstorms Warnings and 2
Special Marine Warnings were issued for this severe weather event.
The Cotton/Canyon Tornado is the only confirmed tornado from this
severe weather event at this time. While funnel clouds were
reported with several other storms, there is currently no evidence
that any of the other storms produced a tornado that reached the
ground and produced damage. This assessment is subject to change
as additional reports are received and in reviewing satellite
imagery over the coming days and weeks.

..Canyon/Cotton Tornado...

Rating:                 EF1
Estimated Peak Wind:    105 mph
Path Length /statute/:  5.9 miles
Path Width /maximum/:   200.0 yards
Fatalities:             0
Injuries:               0

Start Date:             09/19/2024
Start Time:             05:05 PM CDT
Start Location:         4 N Canyon / St. Louis County / MN
Start Lat/Lon:          47.0981 / -92.4726

End Date:               09/19/2024
End Time:               05:18 PM CDT
End Location:           2 E Cotton / St. Louis County / MN
End Lat/Lon:            47.1741 / -92.4182

Survey Summary:
A supercell thunderstorm formed halfway between Meadowlands and
Canyon, MN between 4:35 to 4:40 PM on Thursday September 19, 2024.
As the strong thunderstorm continued to show potential for
producing a tornado, the National Weather Service office in
Duluth, MN issued a Severe Thunderstorm Warning at 4:44 PM for
this storm. The strong storm moved eastward over unpopulated
marshes immediately north of Lake Nichols Road about 4 miles
north-northwest of Canyon, MN by 5:00 PM. Meteorologists at the
National Weather Service issued a Tornado Warning for this storm
at 4:55 PM as early signs of tornadic development appeared on
radar, and a short time later a tornado was confirmed by trained
spotters and law enforcement. Visible tree damage from the
tornado, estimated to have begun at 5:05 PM CDT, was first
observed on the west side of US Highway 53 about 4.5 miles south
of Cotton, MN with pine trees snapped at the base. The tornado
continued to move northeastward to uproot trees along Three Lakes
Road about one-half mile east of the U.S. Highway 53 intersection.
The storm began to move more north-northeastward so the tornado
track shifted more northward with the most widespread surveyed
damage seen along Bug Creek Road about 2.5 miles east-southeast
of Cotton, MN. Over 50 pine trees and numerous clusters of aspen
trees were observed to be snapped at the base and/or uprooted,
estimated to have occurred at around 5:15 PM. A few still-standing
pine trees had metal sheets lofted and wrapped around them. Minor
to moderate structure damage was reported by two property owners
along Bug Creek Road before the tornado passed northward over the
Whiteface River. Towards 5:18 PM, the tornado began to weaken and
finally lifted off the ground. The last uprooted trees, 4 aspen,
were last observed at the intersection of Comstock Lake Road and
Melrude Road 2.7 miles east of Cotton, MN. In total, the tornado
was on the ground for a total of 5.9 miles and around 13 minutes.
The damage rating from the NWS Duluth Storm Survey team resulted
in an EF-1 rating with winds estimated at 105 mph. There were a
total of 2 Tornado Warning in effect from 4:55 PM to 5:45 PM for
this tornadic supercell thunderstorm.

&&

EF Scale: The Enhanced Fujita Scale classifies tornadoes into the
following categories:

EF0...Weak......65 to 85 mph
EF1...Weak......86 to 110 mph
EF2...Strong....111 to 135 mph
EF3...Strong....136 to 165 mph
EF4...Violent...166 to 200 mph
EF5...Violent...>200 mph

NOTE:
The information in this statement is preliminary and subject to
change pending final review of the event and publication in NWS
Storm Data.

$$

JDS/NLy/JJM