The stormy mid-summer of 2016 continues, with severe storms striking northern Minnesota yet again.
A line of intense thunderstorms swept across Minnesota during the overnight hours of July 20-21. Damage was widespread across the northern quarter of the state, with pockets of concentrated damage noted near Bemidji, the Brainerd Lakes area, Duluth, and the Boundary Waters.
The storms formed in central North Dakota during the afternoon of July 20 and moved into northwest Minnesota at dusk. A wind gust of 83mph was clocked at the Hallock Airport in Kittson County at 9:34pm. The storms continued to move to the east and southeast causing damage as they went, including flipping over planes at the Bemidji Airport and peeling off roofs on steel-clad buildings in town. At 1am July 21 the storms reached Park Rapids in Hubbard County and downed trees. A wind gust was measured at 55mph at the Park Rapids Airport.
By 3am the storms moved into the Duluth area, where the ground was saturated from previous storms, making it even easier for the strong winds to topple large trees. Widespread power outages resulted, and at least 75,000 Minnesota Power customers lost service. The storms also moved through the Boundary Waters Canoe Area Wilderness, tragically killing two campers on Basswood Lake in Quetico, just across the Minnesota border in Ontario.
The southern edge of the storms also moved through the Twin Cities metro area between 3:30 and 5am, with gusty winds out ahead of the storms waking people out of bed and causing minor tree damage along with spotty power outages.
Perhaps the only real "benefit" of the stormy night was its effect on the ongoing heat wave. Overnight temperatures had been stuck in the unusually warm low and mid-80s at many locations, but the cooler air rushing out ahead of the storms dropped temperatures into the low 70s. This storm-aided cooling took the edge off the intense heat later in the afternoon, with highs topping out in the high 80s to mid-90s, as opposed to the low 90s to near 100 that had been forecast.
This damaging thunderstorm wind event appears to fit the definition of a derecho (pronounced "deh-rey-cho"), because it produced a nearly continuous swath of damage reports exceeding 250 miles in length, with some spatially distinct gusts of at least 75 mph. As a testament to this storm's reach, many different NWS offices were affected and produced event summaries:
Below are storm reports gathered by the National Weather Service
PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1238 PM CDT THU JUL 21 2016 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0810 PM HAIL 2 N ROCKLAKE 48.82N 99.25W 07/20/2016 E1.00 INCH TOWNER ND PUBLIC 0815 PM TSTM WND GST 1 N BAKER 48.18N 99.65W 07/20/2016 M65.00 MPH BENSON ND MESONET PEAK WIND MEASURED BY THE NDAWN SENSOR. 0815 PM TSTM WND DMG 8 NNW ESMOND 48.14N 99.83W 07/20/2016 BENSON ND CO-OP OBSERVER TREES UPROOTED. POWER OUTAGES. 0833 PM TSTM WND GST LEEDS 48.29N 99.44W 07/20/2016 E60.00 MPH BENSON ND PUBLIC 0930 PM TSTM WND GST 1 W BOWESMONT 48.69N 97.20W 07/20/2016 M53.00 MPH PEMBINA ND MESONET PEAK WIND MEASURED AT THE RWIS ALONG INTERSTATE 29. 0934 PM TSTM WND GST HALLOCK 48.77N 96.94W 07/20/2016 M83.00 MPH KITTSON MN ASOS 0940 PM TSTM WND GST 2 WSW DONALDSON 48.56N 96.94W 07/20/2016 M51.00 MPH KITTSON MN MESONET PEAK WINDS MEASURED AT THE RWIS SENSOR ALONG HWY 11. 1047 PM TSTM WND GST 3 NE BADGER 48.81N 95.97W 07/20/2016 M54.00 MPH ROSEAU MN MESONET PEAK WINDS MEASURED AT THE RWIS STATION ALONG HWY 11. 1055 PM TSTM WND GST 2 NW TABOR 48.10N 96.89W 07/20/2016 M65.00 MPH POLK MN MESONET PEAK WINDS MEASURED AT A PERSOANL WEATHER STATION. 1103 PM TSTM WND GST 10 W ADA 47.30N 96.73W 07/20/2016 M52.00 MPH NORMAN MN MESONET PEAK WINDS MEASURED AT THE HWY 200 RWIS SENSOR. 1117 PM TSTM WND GST 5 NNE HILLSBORO 47.47N 97.02W 07/20/2016 M51.00 MPH TRAILL ND MESONET PEAK WINDS MEASURED AT A PERSONAL WEATHER STATION. 1141 PM TSTM WND GST 5 WNW HOPE 47.35N 97.82W 07/20/2016 M58.00 MPH STEELE ND TRAINED SPOTTER PEAK WIND MEASURED AT A PERSONAL WEATHER STATION. COMMERCIAL POWER IS OUT IN THAT AREA. 1151 PM TSTM WND GST 1 N ADA 47.31N 96.51W 07/20/2016 M53.00 MPH NORMAN MN MESONET PEAK WINDS MEASURED AT THE NDAWN STATION. 1203 AM TSTM WND GST 3 NNW FARGO 46.92N 96.84W 07/21/2016 M69.00 MPH CASS ND ASOS PEAK WIND OF 60 KNOTS MEASURED AT THE FARGO AIRPORT /KFAR/. 1204 AM TSTM WND GST 3 S WAUKON 47.33N 96.13W 07/21/2016 M51.00 MPH NORMAN MN MESONET PEAK WINDS MEASURED AT THE NDAWN STATION. 1205 AM TSTM WND DMG 10 SE FERTILE 47.43N 96.14W 07/21/2016 NORMAN MN TRAINED SPOTTER TWO BOX ELDER TREES DOWNED. THE LARGER TREE WAS APPROXIMATELY 2 FEET IN DIAMETER. 1208 AM HAIL 18 S BAUDETTE 48.45N 94.59W 07/21/2016 M2.00 INCH LAKE OF THE WOODS MN PUBLIC PICTURE RELAYED FROM BROADCAST MEDIA VIA SOCIAL MEDIA 1210 AM TSTM WND DMG HORACE 46.76N 96.90W 07/21/2016 CASS ND BROADCAST MEDIA TIN ROOF DAMAGED. 1211 AM TSTM WND GST 3 S THIEF RIVER FALLS 48.07N 96.18W 07/21/2016 M51.00 MPH PENNINGTON MN AWOS PEAK WINDS MEASURED AT THE THIEF RIVER FALLS AIRPORT /KTVF/. 1211 AM TSTM WND GST 4 S MAHNOMEN 47.26N 95.97W 07/21/2016 M71.00 MPH MAHNOMEN MN MESONET PEAK WINDS MEASURED AT THE RWIS ALONG HWY 59. 1215 AM TSTM WND DMG 4 E WASKISH 48.16N 94.43W 07/21/2016 BELTRAMI MN CO-OP OBSERVER MAPLE TREE OF 5 TO 6 INCH DIAMETER WAS UPROOTED. SMALLER TWIGS BLOWN SOME 200 FEET FROM TREE. 1217 AM TSTM WND GST 2 SE DILWORTH 46.85N 96.67W 07/21/2016 M55.00 MPH CLAY MN MESONET PEAK WINDS MEASURED AT THE RWIS STATION ALONG INTERSTATE 94. 1228 AM TSTM WND GST 2 W LAKE PARK 46.88N 96.14W 07/21/2016 M56.00 MPH BECKER MN MESONET PEAK WINDS MEASURED AT THE LAKE PARK RWIS ALONG HIGHWAY 10. 1235 AM TSTM WND GST 3 W DETROIT LAKES 46.81N 95.91W 07/21/2016 M67.00 MPH BECKER MN AWOS PEAK WINDS MEASURED AT THE DETROIT LAKES AIRPORT /KDTL/. 1244 AM TSTM WND DMG 1 SE DETROIT LAKES 46.80N 95.83W 07/21/2016 BECKER MN LAW ENFORCEMENT LARGE TREE BRANCHES AND LIMBS BROKEN DOWN AROUND TOWN. 1250 AM TSTM WND DMG 2 NE LAKE ITASCA 47.27N 95.18W 07/21/2016 CLEARWATER MN PUBLIC TWO TREE REPORTED SNAPPED IN A YARD. 1258 AM TSTM WND DMG WILTON 47.51N 94.99W 07/21/2016 BELTRAMI MN LAW ENFORCEMENT MATURE TREES BROKEN DOWN IN WILTON. POWER LINES DOWN AS WELL. 0100 AM TSTM WND DMG 7 NNW PARK RAPIDS 47.01N 95.12W 07/21/2016 HUBBARD MN TRAINED SPOTTER ESTIMATED 70 MPH WINDS SUFFICIENT TO UPROOT 3 LARGE TREES APPROXIMATELY 12 INCHES IN DIAMETER. SOIL SOFTENED BY RECENT RAINFALL. 0102 AM TSTM WND DMG 4 ENE EMMAVILLE 47.09N 94.90W 07/21/2016 HUBBARD MN TRAINED SPOTTER LARGE TREE BRANCHES AND LIMBS BROKEN DOWN AROUND CAMP WILDERNESS. POWER OUTAGE REPORTED. 0105 AM TSTM WND GST 3 S PARK RAPIDS 46.87N 95.06W 07/21/2016 M55.00 MPH HUBBARD MN AWOS PEAK WINDS MEASURED AT TEH PARK RAPIDS AIRPORT /KPKD/. 0105 AM TSTM WND GST 3 WNW BEMIDJI 47.50N 94.94W 07/21/2016 M60.00 MPH BELTRAMI MN AWOS PEAK WINDS MEASURED AT THE BEMIDJI AIRPORT /KBJI/. 0113 AM TSTM WND DMG BEMIDJI 47.48N 94.88W 07/21/2016 BELTRAMI MN EMERGENCY MNGR NUMEROUS LARGE TREES BROKEN DOWN AROUND TOWN. ROOFING BLOWN OFF BUILDINGS. 0115 AM TSTM WND GST CHAMBERLAIN 46.91N 94.72W 07/21/2016 M52.00 MPH HUBBARD MN MESONET PEAK WINDS MEASURED AT THE RWIS ON HWY 64. 0125 AM TSTM WND GST 6 ENE PELICAN RAPIDS 46.60N 95.97W 07/21/2016 M60.00 MPH OTTER TAIL MN MESONET PEAK WINDS MEASURED AT A PERSONAL WEATHER STATION.