After a dry November a pattern change would occur the week of November 25th. The first event lead to elevated fire weather concerns over much of interior northern California. It was followed by a fairly impactful and unseasonably cold winter storm. Snow levels were generally forecast to be around 1500 to 2000 feet, with lower snow levels forecast for the Redding area. This system ended up heavily impacting holiday travel, causing chain controls to be in place, in addition to brief closures of Interstate 5 and full closures of Ebbetts Pass/Route 4 in Alpine County, Monitor Pass/Route 89 (Alpine/Mono) and Sonora Pass/Route 108 in Tuolumne and Mono counties due to winter conditions. Towards the end of the storm, Interstate 80 was closed November 29 to 30th for 12 hours from Colfax to the California/Nevada state line. Significant loss to commerce is expected because of this system. This storm ended up bringing two to three feet of snow to the Sierra.

Winter Storm in NORTHEAST FOOTHILLS/SACRAMENTO VALLEY, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

The CoCoRaHS observer reported 11.5 inches of snow accumulation at 1.7 south-southeast of Nevada City. Elevation of the reporter's location is 2477 feet.

Winter Weather in NORTHERN SACRAMENTO VALLEY, CALIFORNIA
From 26-NOV-19 22:00:00 to 27-NOV-19 07:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A member of the public reported two to three inches of snow fell near downtown Redding overnight. Elevation around 564 feet.

Winter Weather in SHASTA LAKE/NORTH SHASTA COUNTY, CALIFORNIA
From 26-NOV-19 13:38:00 to 26-NOV-19 13:38:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

One inch of snow was measured on the ground at the Whiskeytown Reservoir.

Winter Storm in MT SHASTA/WESTERN PLUMAS COUNTY, CALIFORNIA
From 26-NOV-19 10:00:00 to 27-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

At 600 AM on November 27 a COOP observer reported 6 inches of new snow accumulation in Shingletown. Elevation 3491 feet.

Winter Weather in SHASTA LAKE/NORTH SHASTA COUNTY, CALIFORNIA
From 26-NOV-19 13:00:00 to 26-NOV-19 13:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported two inches of snow on the ground at Sims.

Winter Weather in SHASTA LAKE/NORTH SHASTA COUNTY, CALIFORNIA
From 26-NOV-19 21:30:00 to 26-NOV-19 21:30:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter near Sims, CA reported 2 inches of new snow today. Heavy snow occurring now. Elevation 2500 feet.

Winter Storm in MT SHASTA/WESTERN PLUMAS COUNTY, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The COOP observer in Chester, CA at an elevation of 4530 feet, reported 9 inches of new snow accumulation.

Winter Storm in NORTHEAST FOOTHILLS/SACRAMENTO VALLEY, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

A CoCoRaHS observer reported at  5.5 inches of snow accumulation 1.3 north-northeast of Grass Valley, CA. Observer's elevation is 2411 feet.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Caltrans reported 36 inches of snow accumulation at Donner Summit. This is a 48 hour snow total and the elevation for this report is 7239 feet.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Bear Valley Ski Resort reported 22 inches of snow accumulation at an elevation 6600 feet.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Caltrans reported 24 inches of snow accumulation at Camp Connell, elevation 5000 feet, and SnoPark 108, elevation 6200 feet. Farther south, at their Longbarn station, elevation 5000 feet, 15 inches of snow were measured. These snow amounts are a 48 hour storm total snow.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Caltrans reported 25 inches of snow accumulation at Kingvale. This is a 48 hour snow total with the report's elevation being 6100 feet.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A local media station reported 12 inches of new snow accumulation at Pollock Pines.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter in Pacific House, at an elevation of 3489 feet, reported that the storm total snow was 17.5 inches.

Winter Storm in MOTHERLODE/CAMPTONVILLE TO GROVELAND, CALIFORNIA
From 26-NOV-19 10:00:00 to 28-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

The CoCoRaHS observer in Tolumne City, at an elevation around 2569 feet, reported 9.8 inches of snow accumulation.

Winter Weather in CLEAR LAKE/SOUTHERN LAKE COUNTY, CALIFORNIA
From 26-NOV-19 10:00:00 to 27-NOV-19 16:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter called to report 2 to 3 inches of snow accumulation on the ground. At the time of report, moderate to heavy snow was still falling.

Winter Storm in BURNEY BASIN/EASTERN SHASTA COUNTY, CALIFORNIA
From 29-NOV-19 18:00:00 to 30-NOV-19 05:30:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Whiteout conditions brought an extended period of low to zero visibility to Interstate 80 over the Sierra. Blue Canyon Airport ASOS reported visibility less than 1/4 mile in heavy snow Friday evening through early Saturday. I-80 was shutdown 6 pm PST Friday November 29, 2019. Westbound I-80 was opened around 4:30 am and eastbound I-80 was reopened around 5:30 am on Saturday November 30, 2019. Other highways such as Highway 50 and Highway 20 were also intermittently shutdown throughout the night. Travel and commerce across I-80 over the Sierra was impacted for around 12 hours. Loss to commerce is generally projected to be $4.75 million an hour for an I-80 shutdown.