Bands of snow developed over northeast Colorado into the northern mountains and foothills on the 13th, which then intensified overnight.  The heavy snow then gradually shifted southward on the 14th and covered much of the area.  The snow slowly decreased in the evening with only some lingering light snow across the plains continuing into the morning of the 15th.  North winds increased to 25 to 35 mph, on the 14th, with gusts up to 50 mph.  This produced blizzard conditions along the I-25 Corridor from Palmer Divide north to the Wyoming border.   Denver International Airport runways were closed, from noon on 14th until 2 pm on the 15th, with over 2000 flights canceled.  All major Interstates were closed except for those areas around Denver and  Fort Collins.  Extensive drifting snow was observed, with drifts anywhere from 3  to 7 feet deep.  The heavy wet snow caused extensive tree damage and produced power outages. Xcel stated the number of customers in northern Colorado affected by power outages exceeded 15,000. Many were left powerless overnight as crews were unable to reach downed power lines. The majority of the outages were in Weld County.
Localized amounts up to 4 feet were reported in the mountains and foothills of Larimer County; a trained spotter near Buckhorn Mountain measured an impressive 48.5 inches of snow.  Snowfall amounts in the Front Range Mountains and Foothills ranged from 20 to 40 inches, with 18 to 30 inches reported along the I-25 Corridor.  The official snow for Denver was 27.1 which was the 4th largest storm on record since 1882.

Winter Storm in JEFFERSON & W DOUGLAS COUNTIES ABOVE 6000 FEET / GILPIN / CLEAR CREEK / NE PARK COUNTIES BELOW 9000 FEET, COLORADO
From 12-MAR-21 23:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  24 inches near Roxborough Park; 20 inches near Crescent Village and Evergreen; 14 inches Chatfield Reservoir; and 13 inches near White Ranch Open Space.

Winter Storm in N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 14-MAR-21 11:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  28 inches near Buckley AFB; 27.1 inches at Denver International Airport; 26 inches, 3 miles east of Cherry Creek Reservoir; 25 inches in Aurora; 24 inches near Englewood; 19.7 inches, 2 miles east of Denver; 18.4 inches, 5 miles southeast of Commerce City; 17 inches, 4 miles east-southeast of Denver.

Blizzard in BOULDER & JEFFERSON COUNTIES BELOW 6000 FEET / W BROOMFIELD COUNTY, COLORADO
From 13-MAR-21 11:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Strong winds compounded with heavy snowfall made the roadways impassable in the afternoon and evening.  Peak wind gusts to 50 mph produced extensive drifting snow.  Drifts ranged from 3 to 6 feet deep.

Blizzard in N DOUGLAS COUNTY BELOW 6000 FEET / DENVER / W ADAMS & ARAPAHOE COUNTIES / E BROOMFIELD COUNTY, COLORADO
From 13-MAR-21 11:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Strong winds compounded with heavy snowfall made the roadways impassable in the afternoon and evening.  Peak wind gusts to 48 mph produced extensive drifting snow.  Drifts ranged from 3 to 6 feet deep.

Blizzard in LARIMER COUNTY BELOW 6000 FEET / NW WELD COUNTY, COLORADO
From 14-MAR-21 11:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Strong winds compounded with heavy snowfall made the roadways impassable in the afternoon and evening.  Peak wind gusts to 49 mph produced extensive drifting snow.  Drifts ranged from 3 to 6 feet deep.

Blizzard in C & S WELD COUNTY, COLORADO
From 13-MAR-21 11:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Strong winds compounded with heavy snowfall made the roadways impassable in the afternoon and evening.  Peak wind gusts to 45 mph produced extensive drifting snow.  Drifts ranged from 3 to 7 feet deep.

Winter Storm in ELBERT / C & E DOUGLAS COUNTIES ABOVE 6000 FEET, COLORADO
From 13-MAR-21 05:00:00 to 14-MAR-21 11:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  28.4 inches near Parker; 25.8 inches, 9 miles north-northeast of Kiowa; 23.5 inches in Elizabeth, 23 inches near Castle Pines and Ponderosa Park,  18.5 inches near Lone Tree; with 17 inches near Elizabeth.

Blizzard in ELBERT / C & E DOUGLAS COUNTIES ABOVE 6000 FEET, COLORADO
From 13-MAR-21 11:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Strong winds compounded with heavy snowfall made the roadways impassable in the afternoon and evening.  Peak wind gusts to 52 mph produced extensive drifting snow.  Drifts ranged from 3 to 6 feet deep.

Winter Storm in NE WELD COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 15-MAR-21 03:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included 12 inches near Briggsdale.

Winter Storm in MORGAN COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 15-MAR-21 03:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  11.2 inches near Gary; 8 inches around Fort Morgan, with 7 inches near Wiggins.

Winter Storm in BOULDER & JEFFERSON COUNTIES BELOW 6000 FEET / W BROOMFIELD COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 14-MAR-21 11:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  29.5 inches in northwest Arvada; 25.5 inches near Longmont and Louisville; 24 inches near Erie, 22.5 inches near Broomfield; 22 inches near Wheat Ridge; 21 inches near Lafayette; 20.5 inches in southwest Boulder; and 18 inches near Lakewood.

Winter Storm in C & E ADAMS & ARAPAHOE COUNTIES, COLORADO
From 13-MAR-21 05:00:00 to 15-MAR-21 03:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  24 inches, 3 miles south-southeast of Arapahoe Park; 14.8 inches, 4 miles south of Bennett; 10 inches near Byers.

Winter Storm in LARIMER COUNTY BELOW 6000 FEET / NW WELD COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 14-MAR-21 11:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included 28.5 inches near Loveland and 23 inches in west Fort Collins.

Winter Weather in N & NE ELBERT COUNTY BELOW 6000 FEET / N LINCOLN COUNTY, COLORADO
From 13-MAR-21 00:00:00 to 15-MAR-21 05:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm totals included:  9 inches near Agate; 5.8 inches near Hugo, with 4.5 inches in Limon.

Winter Storm in C & S WELD COUNTY, COLORADO
From 13-MAR-21 05:00:00 to 14-MAR-21 11:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included: 25 inches in Firestone; 21 inches near Johnstown; 18 inches near Frederick; 17.6 inches near Erie; with 11.2 inches in Evans.

Winter Weather in WASHINGTON COUNTY, COLORADO
From 13-MAR-21 00:00:00 to 15-MAR-21 05:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Storm totals included 13 inches near Woodlin School.

Winter Storm in S & E JACKSON / LARIMER / N & NE GRAND / NW BOULDER COUNTIES ABOVE 9000 FEET, COLORADO
From 12-MAR-21 23:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: SNOTEL

Storm totals ranged from 8 to 12 inches.

Winter Storm in LARIMER & BOULDER COUNTIES BETWEEN 6000 & 9000 FEET, COLORADO
From 12-MAR-21 23:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: Trained Spotter

Storm totals included:  48.5 inches near Buckhorn Mountain; 42 inches, 8 miles northeast of Four Corners; 41.5 inches near Aspen Springs; 41 inches near Pingree Park; 36.5 inches near Horsetooth Mountain; 33 inches, 7 miles southeast of Cherokee Park; 31 inches 7 miles east-northeast of Virginia Dale; 30 inches near Campion, Pinecliffe and 7 miles west of Rustic; 28.5 inches near Jamestown; 28 inches near Laporte; 26 inches near Estes Park and Nederland; 24.5 inches near Glen Haven; 23.5 inches near Berthoud and 23 inches near Eldorado Springs.

Winter Storm in S & SE GRAND / W CENTRAL & SW BOULDER / GILPIN / CLEAR CREEK / SUMMIT / N & W PARK COUNTIES ABOVE 9000 FEET, COLORADO
From 12-MAR-21 23:00:00 to 14-MAR-21 23:00:00 (MST-7)
Reported by: SNOTEL

Storm totals included: 32.4 inches near Blue Valley; 30 inches, 3 miles south-southeast of Silver Plume; with 17.5 inches near Winter Park Ski Area.