Severe Weather and Tornadoes, July 17-18, 2020

outbreak and risk map
Map of severe weather risk areas and severe storm reports through 7 AM CDT on July 18, 2020.
 
Courtesy: NOAA Storm Prediction Center

Two waves of severe thunderstorms pounded parts of Minnesota, first from the evening of Friday July 17th into the following morning, and then again in the evening of Saturday July 18th.

The thunderstorms erupted amid a potent combination of summertime heating and strong upper-level winds. For the first wave of storms, forecasters at NOAA's Storm Prediction Center had suspected the storms could be unusually severe, and placed much of central and northern Minnesota in a rare, "Moderate Risk" for severe weather. They followed this dire outlook with an even more unusual "Particularly Dangerous Situation" (PDS) Severe Thunderstorm Watch, indicating the potential for a long path of destructive winds.

The storms formed in North Dakota during Friday afternoon, and marched into Minnesota during evening and overnight. Widespread damaging winds were reported in northwestern, northern, and parts of central Minnesota, though mercifully, the outbreak was slightly less destructive than had been feared. The storms did produce two short-lived, late-night tornadoes in east-central Minnesota.

On Saturday, as dew points surged into the upper 70s F with temperatures in the mid-80s to low-90s, the atmosphere destabilized and new storms formed over the eastern half of the state. These storms produced large hail and wind damage throughout the Arrowhead, and storms developing near sunset went on to produce tornadoes in Washington County.

Following are damage reports and tornado damage surveys from the Grand Forks and Chanhassen National Weather Service offices.

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
510 PM CDT SAT JUL 18 2020
..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
PEAK WIND MEASURED AT AN RWIS STATION ALONG HIGHWAY 2.
0449 PM     TSTM WND GST     8 W ARGYLE              48.34N 96.99W
07/17/2020  M58.00 MPH       Marshall           MN   MESONET
PEAK WINDS MEASURED AT A PERSONAL WEATHER STATION.
0505 PM     TSTM WND DMG     EAST GRAND FORKS        47.93N 97.02W
07/17/2020                   POLK               MN   BROADCAST MEDIA
NUMEROUS LARGE BRANCHES AND LIMBS BROKEN DOWN AROUND
TOWN. A LARGE OLD TREE SNAPPED. PHOTOS AND REPORTS POSTED
VIA SOCIAL MEDIA
0506 PM     TSTM WND GST     ARGYLE                  48.34N 96.82W
07/17/2020  E90.00 MPH       Marshall           MN   PUBLIC
BLEACHERS AT THE FOOTBALL FIELD WERE ROLLED AND
DESTROYED. A ROOF WAS PEELED OFF A SHOP. GRAIN ELEVATOR
COMPLEX HAD TOP AUGER TORN OFF AND LARGE BIN CAVED IN.
PHOTO AND REPORT POSTED VIA SOCIAL MEDIA. TIME ESTIMATED
BASED ON RADAR. PEAK WINDS ESTIMATED TO 90 MPH.
0515 PM     TSTM WND GST     2 NNW CROOKSTON         47.80N 96.62W
07/17/2020  M56.00 MPH       Polk               MN   AWOS
PEAK WINDS MEASURED AT THE CROOKSTON AIRPORT /KCKN/.
0529 PM     TSTM WND DMG     1 NW NEWFOLDEN          48.37N 96.35W
07/17/2020                   Marshall           MN   BROADCAST MEDIA
BALL FIELD DUGOUT BLOWN OVER. REPORT AND PHOTO POSTED VIA
SOCIAL MEDIA.
0540 PM     TSTM WND DMG     7 N CLIMAX              47.71N 96.81W
07/17/2020                   Polk               MN   PUBLIC
TREE BLOWN DOWN OVER POWER LINES.
0545 PM     TSTM WND DMG     MENTOR                  47.70N 96.14W
07/17/2020                   POLK               MN   PUBLIC
TREE DAMAGE IN TOWN FROM 545 THROUGH 550 PM CDT.
0545 PM     TSTM WND GST     2 N HOLT                48.32N 96.19W
07/17/2020  M73.00 MPH       Marshall           MN   FIRE DEPT/RESCUE
PEAK WIND MEASURED WITH A PERSONAL WEATHER STATION.
0546 PM     TSTM WND DMG     1 NW THIEF RIVER FALLS  48.12N 96.19W
07/17/2020                   Pennington         MN   PUBLIC
TREES UPROOTED ON NORTHWEST SIDE OF TOWN. REPORTS AND
PHOTOS POSTED VIA SOCIAL MEDIA.
0549 PM     TSTM WND GST     2 SSW THIEF RIVER FALLS 48.09N 96.19W
07/17/2020  M61.00 MPH       Pennington         MN   AWOS
PEAK WIND MEASURED AT THE THIEF RIVER FALLS AIRPORT
/KTVF/.
0550 PM     TSTM WND GST     2 S BROOKS              47.79N 96.00W
07/17/2020  M54.00 MPH       Red Lake           MN   MESONET
PEAK WINDS MEASURED AT AN RWIS STATION.
0555 PM     TSTM WND DMG     2 NE MAPLE BAY          47.66N 96.19W
07/17/2020                   Polk               MN   PUBLIC
AT LEAST ONE TREE WAS DOWN ON A CAMPER/TRAILER AT THE
POLK COUNTY PARK. LARGE TREES WERE BLOWN DOWN AT VARIOUS
LOCATIONS AROUND MAPLE LAKE. PHOTOS AND REPORTS POSTED
VIA SOCIAL MEDIA. TIMES VARIED BETWEEN 550 AND 6 PM CDT.
0620 PM     TSTM WND DMG     4 SE HENDRUM            47.22N 96.75W
07/17/2020                   Norman             MN   PUBLIC
TREES BLWON DOWN IN A SHELTERBELT. PHOTO AND REPORT
POSTED VIA SOCIAL MEDIA.
0630 PM     TSTM WND DMG     4 SE GEORGETOWN         47.04N 96.73W
07/17/2020                   Clay               MN   PUBLIC
TREE BLOWN DOWN IN YARD.
0637 PM     TSTM WND DMG     CLEARBROOK              47.69N 95.43W
07/17/2020                   CLEARWATER         MN   PUBLIC
SMALL TREE BLOWN DOWN IN TOWN. PHOTO AND REPORT POSTED
VIA SOCIAL MEDIA. TIME ESTIMATED BASED ON RADAR.
0641 PM     TSTM WND GST     5 SSE MAHNOMEN          47.25N 95.93W
07/17/2020  M55.00 MPH       Mahnomen           MN   MESONET
PEAK WIND MEASURED AT AN RWIS STATION.
0655 PM     TSTM WND DMG     GLYNDON                 46.87N 96.58W
07/17/2020                   CLAY               MN   BROADCAST MEDIA
ROOFING WAS TORN OFF A TRAILER HOME. REPORT AND PHOTO
POSTED VIA SOCIAL MEDIA.
0703 PM     TSTM WND DMG     ALIDA                   47.38N 95.23W
07/17/2020                   CLEARWATER         MN   PUBLIC
NUMEROUS LARGE BRANCHES AND LIMBS BROKEN DOWN. REPORT
POSTED VIA SOCIAL MEDIA. TIME ESTIMATED BASED ON RADAR.
0710 PM     TSTM WND DMG     5 W BEMIDJI             47.48N 94.99W
07/17/2020                   Beltrami           MN   PUBLIC
SEVERAL TREES BLOWN DOWN.
0715 PM     TSTM WND DMG     3 SE SOLWAY             47.49N 95.08W
07/17/2020                   Beltrami           MN   EMERGENCY MNGR
LARGE MATURE TREES SNAPPED AND BLOCKING ROAD. TIME
ESTIMATED BASED ON RADAR.
0735 PM     TSTM WND DMG     BEMIDJI                 47.48N 94.88W
07/17/2020                   BELTRAMI           MN   EMERGENCY MNGR
BRANCHES AND POWER LINES DOWN NEAR THE UNIVERSITY.
0737 PM     TSTM WND DMG     MANY POINT LAKE         47.08N 95.53W
07/17/2020                   Becker             MN   TRAINED SPOTTER
TREES BLOWN DOWN ON MANY POINT SCOUT CAMP ROAD.
0750 PM     TSTM WND DMG     LAKE PARK               46.88N 96.10W
07/17/2020                   BECKER             MN   BROADCAST MEDIA
LARGE TREE SNAPPED. TIME ESTIMATED BASED ON RADAR.
0820 PM     TSTM WND DMG     3 WSW OSAGE             46.90N 95.32W
07/17/2020                   Becker             MN   PUBLIC
TREES DOWN ON HIGHWAY 34.
0824 PM     HAIL             OSAGE                   46.92N 95.26W
07/17/2020  E0.75 INCH       BECKER             MN   PUBLIC
0830 PM     TSTM WND DMG     MENAHGA                 46.75N 95.10W
07/17/2020                   WADENA             MN   PUBLIC
WIND DAMAGE TO PORCH. ESTIMATED WINDS OF 70 TO 80 MPH.
0839 PM     TSTM WND GST     2 SSW PARK RAPIDS       46.89N 95.08W
07/17/2020  M58.00 MPH       Hubbard            MN   ASOS
PEAK WIND MEASURED AT THE PARK RAPIDS AIRPORT /KPKD/. A
FEW TREES BLOWN DOWN IN TOWN.
0840 PM     HAIL             7 N PARK RAPIDS         47.02N 95.06W
07/17/2020  E1.00 INCH       Hubbard            MN   PUBLIC
0845 PM     TSTM WND GST     SEBEKA                  46.63N 95.09W
07/17/2020  E60.00 MPH       WADENA             MN   PUBLIC
0850 PM     TSTM WND DMG     AKELEY                  47.00N 94.73W
07/17/2020                   HUBBARD            MN   BROADCAST MEDIA
TREES BLOWN DOWN. REPORT AND PHOTO POSTED VIA SOCIAL
MEDIA. TIME ESTIMATE BASED ON RADAR.
0930 PM     TSTM WND GST     SEBEKA                  46.63N 95.09W
07/17/2020  E60.00 MPH       WADENA             MN   TRAINED SPOTTER
SECOND BLAST OF WIND GUSTING TO 60 MPH. SEVERAL LARGE
BRANCHES BROKEN DOWN IN A YARD.
0931 PM     HAIL             2 W WADENA              46.44N 95.18W
07/17/2020  E1.25 INCH       Otter Tail         MN   TRAINED SPOTTER
0944 PM     HAIL             VERNDALE                46.40N 95.01W
07/17/2020  E1.00 INCH       WADENA             MN   PUBLIC
REPORT FROM SOCIAL MEDIA.
1050 PM     TSTM WND GST     2 W TENNEY              46.04N 96.50W
07/17/2020  M54.00 MPH       Wilkin             MN   MESONET
PEAK WIND MEASURED AT RWIS STATION
1050 PM     TSTM WND DMG     4 W HOFFMAN             45.83N 95.87W
07/17/2020                   Grant              MN   TRAINED SPOTTER
SEVERAL LARGE TREE BRANCHES AND LIMBS BROKEN DOWN. WINDS
ESTIMATED AT 60 TO 65 MPH.
PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
829 PM CDT SUN JUL 19 2020
...NWS DAMAGE SURVEY FOR EARLY MORNING JULY 18 AND LATE EVENING 
JULY 18, 2020 TORNADO EVENTS - INITIAL ISSUANCE... 
.NORTHWEST ISANTI COUNTY, MN TORNADO...
RATING:                 EF-1
ESTIMATED PEAK WIND:    90 MPH
PATH LENGTH /STATUTE/:  3.0 MILES
PATH WIDTH /MAXIMUM/:   100 YARDS
FATALITIES:             0
INJURIES:               0
START DATE:             JUL 18 2020
START TIME:             1259 AM CDT
START LOCATION:         9 SSE OGILVIE, MN
START LAT/LON:          45.7092 / -93.3803
END DATE:               JUL 18 2020
END TIME:               105 AM CDT
END LOCATION:           7 W BRAHAM, MN
END LAT/LON:            45.7092 / -93.3185
THIS TORNADO WAS EMBEDDED WITHIN A LINE OF SEVERE THUNDERSTORMS
PRODUCING STRAIGHT LINE WIND DAMAGE, BUT A CONCENTRATED AREA OF
DAMAGE EXHIBITING TORNADO CHARACTERISTICS TRACKED ACROSS 
NORTHWEST ISANTI COUNTY. A LOCAL ANEMOMETER MEASURED AN 87 MPH 
GUST. 
.RUSH LAKE, MN TORNADO...
RATING:                 EF-0
ESTIMATED PEAK WIND:    80 MPH
PATH LENGTH /STATUTE/:  1.5 MILES
PATH WIDTH /MAXIMUM/:   100 YARDS
FATALITIES:             0
INJURIES:               0
START DATE:             JUL 18 2020 
START TIME:             124 AM CDT
START LOCATION:         5 SE BRAHAM, MN (WEST SIDE OF RUSH LAKE)
START LAT/LON:          45.6765 / -93.1032
END DATE:               JUL 18 2020
END TIME:               127 AM CDT
END LOCATION:           6 SE BRAHAM, MN (SOUTH SIDE OF RUSH LAKE)
END LAT/LON:            45.6634 / -93.0886
A BRIEF TORNADO SPIN UP WITHIN A LINE OF SEVERE THUNDERSTORMS 
OCCURRED ON THE WEST SIDE OF RUSH LAKE AND TRACKED TO THE SOUTH 
SIDE. BOATS AND DOCKS WERE DAMAGED. SPORADIC STRAIGHT LINE WIND 
DAMAGE OCCURRED SURROUNDING THIS TRACK.
.WOODBURY, MN TO AFTON, MN TORNADO...
RATING:                 EF-0
ESTIMATED PEAK WIND:    65 MPH
PATH LENGTH /STATUTE/:  3.1 MILES 
PATH WIDTH /MAXIMUM/:   50 YARDS 
FATALITIES:             0 
INJURIES:               0
START DATE:             JUL 18 2020
START TIME:             942 PM CDT
START LOCATION:         2 SE WOODBURY, MN
START LAT/LON:          44.8900 / -92.9050
END DATE:               JUL 18 2020
END TIME:               951 PM CDT
END LOCATION:           3 W AFTON, MN
END LAT/LON:            44.9050 / -92.8450
NO DAMAGE WAS FOUND AND NO DAMAGE REPORTS WERE RECEIVED. HOWEVER,
KMPX RADAR CONFIRMED A TORNADO BASED ON A BRIEF TORNADIC DEBRIS
SIGNATURE AND TMSP RADAR TRACKED A COUPLET NORTHEAST ACROSS
SOUTHERN WASHINGTON COUNTY. THEREFORE, THE TORNADO IS RATED EF0.
PATH LENGTH, BEGINNING AND ENDING POINTS, AND BEGINNING AND ENDING
TIMES ARE APPROXIMATE.
.SOUTHERN WASHINGTON COUNTY, MN INTO PIERCE COUNTY, WI TORNADO...
RATING:                 EF-1
ESTIMATED PEAK WIND:    100 MPH
PATH LENGTH /STATUTE/:  9.5 MILES
PATH WIDTH /MAXIMUM/:   400 YARDS
FATALITIES:             0
INJURIES:               0
START DATE:             JUL 18 2020 
START TIME:             953 PM CDT
START LOCATION:         5 N HASTINGS, MN
START LAT/LON:          44.8188 / -92.8441
END DATE:               JUL 18 2020
END TIME:               1020 PM CDT
END LOCATION:           2 SW RIVER FALLS, WI
END LAT/LON:            44.8336 / -92.6571
EXTENSIVE TREE DAMAGE ALONG THE PATH, MANY OF WHICH WERE SNAPPED
ABOUT HALF WAY UP. THE HEAVIEST DAMAGE OCCURRED ON TOP OF A BLUFF AS
THE TORNADO CROSSED THE ST. CROIX RIVER INTO WISCONSIN. A FEW FARM
OUTBUILDINGS WERE ALSO DAMAGED.
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 200MPH
EF5...VIOLENT...>200MPH
NOTE:
THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENTS AND PUBLICATION IN NWS 
STORM DATA. 

 

Updated July 22, 2020

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