A powerful cold front moved across northern Colorado in the morning.  Bands of moderate to heavy snow showers in the mountains resulted in early morning snow squalls. Colorado Department of Transportation had brief road closures along with parts of I-70 due to the limited visibility and hazardous road conditions that accompanied the snow squalls.  Storm totals in the mountains generally ranged from 3.5 to 6.5 inches.  As the cold front swept across the Front Range Foothills, Urban Corridor, and northeast CO plains, very strong post-frontal or bora winds developed. The strongest wind gusts ranged from 70 to 95 mph occurred in and near the foothills, and along and north of the I-76 corridor.
Several trees were knocked down, and then subsequent high winds and blowing dust occurred across the plains. Some of those trees crashed into nearby homes and onto parked automobiles.  Numerous trucks tipped on I-25 and blowing dust resulted in numerous accidents and road closures.  The northbound lanes of I-25 were closed to high profile and lightweight vehicles at Owl Canyon Road near the CO/WY state line due to the high winds. There were overturned semis on I-25, with windows blown out of cars in Boulder and Broomfield.  Larimer County Road 38E, along the southeastern edge of Horsetooth Reservoir, was closed for more than 20 hours because of a downed utility line.  Residents from hundreds of homes in the area were forced to detour through Loveland to get to Fort Collins.  Denver International Airport reported 2,219 flight cancellations and 12,327 delays.
Xcel Energy reported that power outages peaked at about 63,000 customers during this high wind event.  State Highway 52 was closed from New Raymer to Fort Morgan due to an accident and brownout conditions. The Sedgwick County Courthouse and Annex building closed early due to a power outage in Julesburg and forced the communications center to backup power.  The Julesburg school district released all students early due to the outages. The Revere School District in Ovid released students early due to hazardous travel conditions across Sedgwick County. Phillips County also reported scattered power outages, uprooted trees, and some structural damage.

Winter Weather in S & SE GRAND / W CENTRAL & SW BOULDER / GILPIN / CLEAR CREEK / SUMMIT / N & W PARK COUNTIES ABOVE 9000 FEET, COLORADO
From 15-DEC-21 02:00:00 to 15-DEC-21 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals ranged from 3 to 6 inches.  Snow squalls associated with the passage of the cold front resulted in brief road closures along parts of Interstate 70 due to hazardous driving conditions.

High Wind in BOULDER & JEFFERSON COUNTIES BELOW 6000 FEET / W BROOMFIELD COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 81.00 MG
Reported by: Mesonet

Peak wind gusts included:  93 mph near Louisville, 89 mph at Rocky Mountain Metro Airport, 85 mph in southwest Arvada and 79 mph near Marshall.

High Wind in N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 52.00 MG
Reported by: ASOS

Peak wind gusts included:  60 mph at Denver International Airport, with 59 mph at Centennial Airport, Englewood and Littleton.

High Wind in NE WELD COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 68.00 MG
Reported by: Mesonet

Peak wind gusts included 78 mph, 11 miles northwest of Westplains.

High Wind in C & S WELD COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 68.00 MG
Reported by: Mesonet

Peak wind gusts included:  78 mph near Johnstown, 71 mph near Mead, 68 mph near Briggsdale, and 67 mph near Nunn and Severence.

High Wind in MORGAN COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 58.00 MG
Reported by: Mesonet

Peak wind gusts included 67 mph at Fort Morgan Municipal Airport. Power lines were downed in Brush.

High Wind in N & NE ELBERT COUNTY BELOW 6000 FEET / N LINCOLN COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 52.00 MG
Reported by: ASOS

Peak wind gusts included 60 mph at Fort Limon Municipal Airport.

High Wind in LOGAN COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 65.00 MG
Reported by: Mesonet

Peak wind gusts included:  75 mph near Sterling, 71 mph, 5 miles north of Pawnee Pass; 65 mph at Iliff and North Sterling Reservoir, and 62 mph near Peetz.

High Wind in WASHINGTON COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 68.00 MG
Reported by: ASOS

Peak wind gusts included 78 mph in Akron and 69 mph near Union.

High Wind in SEDGWICK COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 56.00 MG
Reported by: Mesonet

Peak wind gusts included 64 mph near Ovid and 62 mph near Julesburg.

High Wind in PHILLIPS COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 70.00 MG
Reported by: Mesonet

Peak wind gusts included 81 mph, 8 miles south of Holyoke and 74 mph just southeast of Holyoke.

Winter Weather in WEST JACKSON & WEST GRAND COUNTIES ABOVE 9000 FEET, COLORADO
From 15-DEC-21 02:00:00 to 15-DEC-21 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals ranged from 4 to 6.5 inches.

Winter Weather in S & E JACKSON / LARIMER / N & NE GRAND / NW BOULDER COUNTIES ABOVE 9000 FEET, COLORADO
From 15-DEC-21 02:00:00 to 15-DEC-21 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals ranged from 3.5 to 6 inches.

High Wind in LARIMER & BOULDER COUNTIES BETWEEN 6000 & 9000 FEET, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 79.00 MG
Reported by: Mesonet

Peak wind gusts included:  91 mph, 3 miles south-southwest of Boulder; 86 mph near  Buckeye, 84 mph, 6 miles southwest of Carr; 79 mph near Nederland, 78 mph near Meeker Park, and 75 mph near Pinecliffe.

High Wind in JEFFERSON & W DOUGLAS COUNTIES ABOVE 6000 FEET / GILPIN / CLEAR CREEK / NE PARK COUNTIES BELOW 9000 FEET, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 83.00 MG
Reported by: Mesonet

Peak wind gusts included:  95 mph, 3 miles north-northeast of White Ranch Open Space; 94 mph at the Junction of Highways 93 and 72; 87 mph at the National Wind Technology Center and near Cheeseman, 85 mph near Floyd Hill, 83 mph near Pleasant View, 80 mph near Genesee, and 79 mph near Aspen Springs and Pinecliffe.

High Wind in LARIMER COUNTY BELOW 6000 FEET / NW WELD COUNTY, COLORADO
From 15-DEC-21 08:00:00 to 15-DEC-21 17:00:00 (MST-7)
Magnitude: 72.00 MG
Reported by: Mesonet

Peak wind gusts included 83 mph near Natural Fort Rest Area and 79 mph near Loveland.