A very strong atmospheric river event brought very heavy snow to the southeast Idaho mountains and the Sun Valley region.   Amounts of over 2 feet of snow were very common in the drawn out event.  51 inches of snow fell at Bald Mountain at the Sun Valley ski resort and the resort shut down January 29th after several avalanches and the death of a skier.

Heavy Snow in SUN VALLEY REGION, IDAHO
From 27-JAN-21 06:00:00 to 30-JAN-21 10:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

An atmospheric river event brought extreme snowfall amounts to the Sun Valley region over several days.   33.5 inches was measured by the COOP in Ketchum.   Other amounts estimated at SNOTEL sites were:  Chocolate Gulch 31 inches, Dollarhide Summit 42 inches, Galena 17 inches, Galena Summit 43 inches, Hyndman 21 inches, and Lost Wood Divide 29 inches.   Bald Mountain at summit of Sun Valley ski resort measured 51 inches of snow.   A 67 year old male died while skiing on January 29th in the extremely deep snow from asyphixiation after suffering an accident.

Avalanche in SUN VALLEY REGION, IDAHO
From 28-JAN-21 15:00:00 to 30-JAN-21 05:00:00 (MST-7)
Crop damage: 0.00K
Reported by: Emergency Manager

Back country skiers triggered avalanches on the Warm Springs side of Bald Mountain.  Skiing operations were shut down on the afternoon of the 29th due to avalanche mitigation at Sun Valley ski resort.  Substantial debris from one of the avalanches caused debris on Warm Springs Road near Ketchum on the 29th.   The debris buried two vehicles.  Warm Springs Road was only open to residents.

Heavy Snow in ARCO-MUD LAKE DESERT, IDAHO
From 27-JAN-21 05:00:00 to 30-JAN-21 04:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

During first day and a half of storm Craters of the Moon measured 15 inches of snow.   Butte County School District 111 closed on the 28th due to the very heavy snow and hazardous travel conditions.

Heavy Snow in LOST RIVER VALLEYS, IDAHO
From 27-JAN-21 04:00:00 to 30-JAN-21 05:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Eleven inches of snow fell at the onset of the storm from the 27th into the 28th at Darlington as measured by a spotter.    Butte County School District 111 was closed due to the heavy snow and hazardous travel conditions on the 28th.

Heavy Snow in WOOD RIVER FOOTHILLS, IDAHO
From 27-JAN-21 04:00:00 to 30-JAN-21 04:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Extremely heavy snow fell in the Wood River Foothills.   The COOP observer in Bellevue measured 12 inches of snow the first two days of the event through the 28th.   The Hailey region had several reports of between 25 and 40 inches of snow for the event.

Heavy Snow in BEAVERHEAD-LEMHI HIGHLANDS, IDAHO
From 27-JAN-21 04:00:00 to 30-JAN-21 04:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Heavy snow fell in the Beaverhead and Lemhi Highlands region.    The COOP observer at Dubois measured 12 inches and the COOP observer at Small measured 11 inches.

Heavy Snow in BEAR RIVER RANGE, IDAHO
From 27-JAN-21 07:00:00 to 30-JAN-21 06:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Estimated SNOTEL snowfall were 15 inches at Emigrant Summit and 13 inches at Franklin Basin.

Heavy Snow in CENTENNIAL MOUNTAINS-ISLAND PARK, IDAHO
From 27-JAN-21 06:00:00 to 30-JAN-21 07:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Estimated SNOTEL snow amounts were 25 inches at Crab Creek, 14 inches at Island Park, and 28 inches at White Elephant.

Heavy Snow in SAWTOOTH-STANLEY BASIN, IDAHO
From 27-JAN-21 05:00:00 to 30-JAN-21 07:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

An estimated 40 inches of snow fell at the Vienna Mine SNOTEL site.

Winter Weather in TETON VALLEY, IDAHO
From 30-JAN-21 12:00:00 to 30-JAN-21 20:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Very strong winds caused extensive blowing and drifting of snow and whiteouts on Idaho route 32.   It was closed around noon on the 30th from Ashton to Tetonia between Idaho 47 and Idaho 33.

Heavy Snow in BIG LOST HIGHLANDS-COPPER BASIN, IDAHO
From 27-JAN-21 04:00:00 to 30-JAN-21 06:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

SNOTEL estimated snow totals were 35 inches at Bear Canyon, 24 inches at Garfield Ranger Station, 31 inches at Smiley Mountain, 18 inches at Stickney Mill, and 45 inches at Swede Peak.

Heavy Snow in LOST RIVER RANGE, IDAHO
From 27-JAN-21 04:00:00 to 30-JAN-21 06:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Estimated SNOTEL amounts were 42 inches at Hilt's Creek and 15 inches at Meadow Lake.