The first widespread winter storm of the season hit western and central Wyoming. The main effects from the storm were focused around central Wyoming. Areas favored by east to northeast flow received the most snow, especially in Johnson and Natrona counties. Areas near Buffalo received the most snow with up to 18 inches reported on the west side of town. In Natrona County, areas around Casper received anywhere from 10 to 18 inches, although amounts dropped substantially farther west. Amounts over 6 inches were also reported in Fremont and Hot Springs counties. In the higher elevations, the eastern slopes of the Bighorn Range had the most with up to 20 inches reported. The snow combined with a gusty wind to close many major roads for a time, including Interstate 25, US 20/26, and US 287.

Winter Storm in BIGHORN MOUNTAINS SOUTHEAST, WYOMING
From 11-OCT-21 04:00:00 to 13-OCT-21 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Heavy snow fell throughout the eastern Bighorn Range. The highest amount was 20 inches at the Soldier Park SNOTEL site.

Winter Storm in NORTHEAST JOHNSON COUNTY, WYOMING
From 11-OCT-21 08:00:00 to 13-OCT-21 09:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy snow fell throughout northern Johnson County, with most locations receiving between 12 and 18 inches. The heavy snow led to the closure of Interstate 25 for several hours.

Avalanche in SOUTHEAST JOHNSON COUNTY, WYOMING
From 11-OCT-21 08:00:00 to 13-OCT-21 09:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy snow fell over portions of southern Johnson County, with the maximum accumulation of 14 inches to the east of Kaycee. The heavy snow led to the closure of Interstate 25 for many hours.

Winter Storm in LANDER FOOTHILLS, WYOMING
From 11-OCT-21 17:00:00 to 12-OCT-21 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Amounts around the Lander and the adjacent foothill communities ranged from 6 to 9 inches, including 7.9 inches at the Lander Airport.

Winter Storm in NATRONA COUNTY LOWER ELEVATIONS, WYOMING
From 11-OCT-21 17:00:00 to 13-OCT-21 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Snowfall amounts around Casper ranged 12 to 18 inches, including 12.7 inches at the Casper-Natrona County International Airport. The heavy snow led to the closure of Interstate 25 as well as US 20/26 west of Casper. Snowfall amounts tapered off to the west with 6 inches reported at Powder River.

Winter Storm in WIND RIVER MOUNTAINS EAST, WYOMING
From 11-OCT-21 23:00:00 to 12-OCT-21 23:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A combination of snow and gusty wind led to the closure of Wyoming Highway 28 over South Pass for several hours on Tuesday, October 12.

Winter Storm in SOUTHWEST BIG HORN BASIN, WYOMING
From 11-OCT-21 10:00:00 to 12-OCT-21 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy snow fell in portions of Hot Springs County. A trained spotter reported 6.5 inches to the northeast of Thermopolis.

Winter Storm in GREEN MOUNTAINS & RATTLESNAKE RANGE, WYOMING
From 11-OCT-21 17:00:00 to 12-OCT-21 22:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A combination of snow and gusty wind led to the closure of US 287 for several hours.

Winter Storm in BIGHORN MOUNTAINS WEST, WYOMING
From 11-OCT-21 07:00:00 to 12-OCT-21 17:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Heavy snow fell in portions of the western Bighorn Range. The highest amount of snow reported was 15 inches at the Bald Mountain SNOTEL site at the north end of the range.

Winter Storm in WIND RIVER BASIN, WYOMING
From 11-OCT-21 17:00:00 to 12-OCT-21 17:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported 8 inches of snow in Hudson. Amounts dropped sharply farther north with Riverton reporting anywhere from 2 to 4 inches of snow.