Circulation around a stalled low pressure system over Colorado produced moist upslope flow combined with sub-freezing temperatures aloft.  The result was periods of heavy wet snow along with gusty north to northeast winds.  Travel was severely impacted  along Interstate 80 from Cheyenne to Arlington due to the poor visibility in falling snow and snow packed roadways.  Twenty-seven persons were injured in a 70 vehicle pileup on eastbound Interstate 80 about 20 miles west of Cheyenne during the late morning of April 16.

Winter Storm in LARAMIE VALLEY, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Eight inches of snow was estimated at Laramie.

Winter Storm in SOUTH LARAMIE RANGE FOOTHILLS, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Six inches of snow was measured 17 miles west-northwest of Cheyenne.  Semitrailers traveling east on Interstate 80 were among 70 vehicles involved in three separate pileups that occurred at mile marker 342, about 20 miles west of Cheyenne near the Harriman Road exit.  Heavy snow reduced visibility to less than a quarter mile at the time of the pileups late Thursday morning.  Of the 27 persons injured, six were serious or critical.

Winter Storm in CENTRAL LARAMIE COUNTY, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Eight inches of snow was reported 10 miles north of Cheyenne.

Winter Storm in SOUTH LARAMIE RANGE FOOTHILLS, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A foot of snow was reported 15 miles northwest of Cheyenne.

Winter Storm in CENTRAL LARAMIE COUNTY, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six inches of snow was reported three miles northeast of Cheyenne.

Winter Storm in CENTRAL LARAMIE COUNTY, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Six inches of snow was measured at the NWS in Cheyenne.

Winter Storm in SNOWY RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The North French Creek SNOTEL site (elevation 10130 ft) estimated 20.4 inches of snow.

Winter Storm in SNOWY RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Sand Lake SNOTEL site (elevation 10050 ft) estimated 24 inches of snow.

Winter Storm in SNOWY RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Brooklyn Lake SNOTEL site (elevation 10240 ft) estimated 29.8 inches of snow.

Winter Storm in SNOWY RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Cinnabar Park SNOTEL (elevation 9574 ft) estimated 30 inches of snow.

Winter Storm in SNOWY RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Medicine Bow SNOTEL site (elevation 10510 ft) estimated 22.8 inches of snow.

Winter Storm in SOUTH LARAMIE RANGE, WYOMING
From 16-APR-15 14:00:00 to 17-APR-15 16:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

The Crow Creek SNOTEL site (elevation 8330 ft) estimated 26.6 inches of snow.