The combination of very high winds and extremely dry conditions produced the most destructive wildfire in Colorado history ($2 Billion), the Marshall Fire.  It was also one of the costliest fires in U.S. history.  The Marshall Fire was driven by wind gusts from 75 mph to 100 mph, as it raced across southeast Boulder County and quickly consumed 6200 acres.  The governor issued a State of Emergency.  U.S. President Joe Biden responded to the fires by expediting a Major Disaster Declaration, unlocking federal aid for individuals and public infrastructure. The Marshall Fire destroyed or damaged over one thousand homes and businesses, along with hundreds of trees.
The fire perimeter included the towns Marshall, Superior, Louisville as well as unincorporated sections of Boulder County.  A total of 45,000 people were evacuated from Superior, Louisville, and portions of Broomfield; 26,000 residents were without power.  In all, 1,094 homes within the fire perimeter were destroyed and 266 homes were damaged.  Seven commercial properties were destroyed and 30 other businesses were damaged. The was one confirmed fatality in Marshall.  An elderly resident in Superior was missing and presumed dead.  Six people suffered minor burns.
In Arvada, a Discount Tire store collapsed.  One employee was treated for minor injuries.  Semi-trucks were blown over along CO93 and C470 which forced road closures.  The high winds smashed car windows.  Just prior to the Marshall Fire, the Middle Fork Fire was reported in northern Boulder County. It was contained that day and no structures were burned.  In Weld County, a grass fire near county roads 19 and 40, forced the evacuation of 4 homes south of Johnstown.  None of the structures were damaged.
The most impressive peak wind reports in this wind event included:  115 mph in northwest Arvada near CO93, 110 mph at the junction of CO93/CO72, 108 mph, 3 miles southwest of Boulder; 103 mph near White Ranch Open Space, 102 mph near Crisman, 98 mph at the National Wind Technology Center; 90 mph at Glen Haven and near Marshall, 81 mph at C470 and south Wadsworth, 79 mph at Livermore, and 75 mph in Boulder.

Wildfire in BOULDER & JEFFERSON COUNTIES BELOW 6000 FEET / W BROOMFIELD COUNTY, COLORADO
From 30-DEC-21 11:15:00 to 30-DEC-21 23:00:00 (MST-7)
Property damage: 2.00B
Reported by: Emergency Manager

Marshall Fire devastated portions of Marshall, Superior and Louisville.  Strong downslope winds, with gusts up to 100 mph, fanned a grass fire that originated near the town of Marshall and quickly spread east to Superior and Louisville.  The fire was the costliest fire in state history, and residential and business property losses alone were estimated to be slightly over $2 Billion.  In all, 1,094 homes were destroyed and 266 homes were damaged.  In addition, 7 commercial properties were destroyed and 30 others sustained damage.  Tens of thousands fled the fire.  Two people died in the fire, while six others were injured.

High Wind in BOULDER & JEFFERSON COUNTIES BELOW 6000 FEET / W BROOMFIELD COUNTY, COLORADO
From 30-DEC-21 08:00:00 to 30-DEC-21 18:30:00 (MST-7)
Magnitude: 94.00 MG
Reported by: Mesonet

Peak wind gusts included:  115 mph in northwest Arvada near Highway 93, 90 mph, 3 miles northwest of Marshall, 75 mph in Boulder. Several mobile homes on route 93 south of Boulder had roof damage from high wind, and tree branches and fences were blown down throughout Boulder.

High Wind in LARIMER & BOULDER COUNTIES BETWEEN 6000 & 9000 FEET, COLORADO
From 30-DEC-21 07:45:00 to 30-DEC-21 19:30:00 (MST-7)
Magnitude: 78.00 MG
Reported by: Mesonet

Peak wind gusts included:  90 mph near Glen Haven, 79 mph near Livermore, 62 mph at Lyons and Virginia Dale, with 60 mph at Buckeye.

High Wind in JEFFERSON & W DOUGLAS COUNTIES ABOVE 6000 FEET / GILPIN / CLEAR CREEK / NE PARK COUNTIES BELOW 9000 FEET, COLORADO
From 30-DEC-21 09:00:00 to 30-DEC-21 18:00:00 (MST-7)
Magnitude: 90.00 MG
Reported by: Mesonet

Peak wind gusts included:  110 mph at the mouth of Coal Creek Canyon near the junction of highways 72 and 93, 103 mph near White Ranch Open Space, 73 mph near I-70 and C470, and 71 mph at Genesee.