A combination of an arctic air mass, a clear sky, a long early January night and a deep, fresh snow pack brought frigid temperatures to much of western and central Wyoming. Four different counties recorded low temperatures under minus 40, including a low of minus 45 East of Rock Springs. All eleven counties in the County Warning Area recorded a temperatures of -30 or lower on the night of January 5-6, 2017.

Extreme Cold/Wind Chill in YELLOWSTONE NATIONAL PARK, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frigid temperatures occurred in Yellowstone Park. Some of the low temperatures included minus 41 degrees at the Lamar Ranger Station and -35 degrees at the northeast entrance to Yellowstone Park.

Extreme Cold/Wind Chill in NORTH BIG HORN BASIN, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The temperature dropped to minus 30 degrees at Greybull.

Extreme Cold/Wind Chill in SOUTHWEST BIG HORN BASIN, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A weather station 9 miles northeast of Thermopolis recorded a low temperatures of minus 33 degrees.

Extreme Cold/Wind Chill in SOUTHEAST JOHNSON COUNTY, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The COOP observer at Kaycee recorded a low temperature of minus 30 degrees.

Extreme Cold/Wind Chill in GREEN MOUNTAINS & RATTLESNAKE RANGE, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The COOP observer reported a low temperature of minus 33 degrees at Jeffrey City.

Extreme Cold/Wind Chill in NATRONA COUNTY LOWER ELEVATIONS, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A weather sensor at Independence Rock recorded a low temperature of minus 41 degrees.

Extreme Cold/Wind Chill in STAR VALLEY, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Very cold temperatures occurred through the Star Valley. Among the coldest temperatures recorded was minus 35 degrees at the Afton airport.

Extreme Cold/Wind Chill in UPPER GREEN RIVER BASIN FOOTHILLS, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Frigid temperatures occurred throughout the region. Some of the coldest temperatures included minus 44 degrees at Bondurant and minus 36 degrees at the Pinedale airport.

Extreme Cold/Wind Chill in UPPER GREEN RIVER BASIN, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Extreme cold occurred through the Upper Green River Basin, including minus 32 degrees at the Farson COOP.

Extreme Cold/Wind Chill in SOUTH LINCOLN COUNTY, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frigid temperatures were common across Southern Lincoln County. Some of the lowest temperatures included minus 40 degrees south of Cokeville and minus 32 degrees at Kemmerer.

Extreme Cold/Wind Chill in ROCK SPRINGS & GREEN RIVER, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Temperatures of minus 30 or below were commonplace across the region, including minus 35 degrees, three miles northwest of Rock Springs.

Extreme Cold/Wind Chill in EAST SWEETWATER COUNTY, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Frigid temperatures occurred across the region. Three locations east of Rock Springs experienced low temperatures of minus 40 degrees or below, including minus 45 degrees at a site 8 miles East of Rock Springs.

Extreme Cold/Wind Chill in JACKSON HOLE, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Frigid temperatures occurred throughout the Jackson Valley. Some of the coldest lows included minus 36 degrees at the Jackson Hole Airport and minus 32 degrees at Moose.

Extreme Cold/Wind Chill in WIND RIVER BASIN, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Brutally cold temperatures occurred on the morning of January 6th. Some of the coldest lows included minus 38 degrees, two miles south of Riverton, minus 33 degrees at the COOP observer and minus 32 degrees at Hudson.

Extreme Cold/Wind Chill in LANDER FOOTHILLS, WYOMING
From 05-JAN-17 21:00:00 to 06-JAN-17 12:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported a low temperature of minus 31 degrees at Lander.