A warm atmospheric river event began early Wednesday, November 28th with an initial wave of rain and snow at higher elevations above 6500 ft. A second wave came through Thursday evening, November 29th through Friday, November 30th, bringing heavier rain and more snow to the highest elevations above 7000 ft. The third wave came through Saturday evening December 1st through Sunday, December 2nd, bringing periods of moderate to heavy rainfall, flooding from overly saturated grounds and high river/stream water levels, and snow above 7000 ft. Windy conditions persisted through the event, especially Wednesday through Saturday, causing trees and tree branches to fall down and localized power outages affecting approximately 10K people. Winds were reported to reach as high as 60-70 mph in the valley/foothill region, and over 100 mph in the mountains.

Winter Weather in MT SHASTA/WESTERN PLUMAS COUNTY, CALIFORNIA
From 01-DEC-12 00:00:00 to 02-DEC-12 06:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

A series of storm waves, associated with a warm atmospheric river event, came through Northern California and dropped several inches of snow for the Sierra Nevada mountains. Snow began in the morning of Nov 28, and dropped about 27 inches of snow at Lower Lassen Peak between Nov 28-30. Additional snow fell with the event, bringing the Lassen storm total to about 39. The most intense 24 hour period occurred between Thursday and Friday with 15 at Lassen, which occurred during our winter storm warning. Winds were reported to gust up to 80-100+ mph at the highest elevations.

Flood in SHASTA, CALIFORNIA
From 02-DEC-12 06:00:00 to 02-DEC-12 10:00:00 (PST-8)
Location: BELLA VISTA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A series of consecutive heavy rainfall events caused creeks and streams to rise rapidly due to ground saturation. Two to three feet of water was reported at the intersection of Highway 299 and Dry Creek Rd, as well as flooding farther northeast on Highway 299 from Montgomery Creek.

Winter Weather in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 01-DEC-12 00:00:00 to 02-DEC-12 12:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

A series of storm waves, associated with a warm atmospheric river event, came through Northern California and dropped several inches of snow for the Sierra Nevada mountains. Over 20 of snow was reported at Sierra at Tahoe (7000-8000 ft) on Nov 28-30, with a storm total of 38 for the whole event. Ebbetts Pass (8765 ft) received 25 on Nov 28-30, with a storm total of 30 through Dec 2. Blue Lakes (8000 ft) received approximately 15 through Nov 30, with a couple more inches that fell through Dec 2. CSS Lab (6855 ft) located along I-80 received approximately 7 through Nov 30, and had a total of 12 as a storm total through Dec 2. The largest accumulations of snowfall occurred Thursday into Friday (Nov 29-30), and again Saturday into Sunday (Dec 1-2). Winds were reported to gust up to 80-100+ mph at the highest elevations.

Flood in SACRAMENTO, CALIFORNIA
From 02-DEC-12 08:00:00 to 02-DEC-12 15:00:00 (PST-8)
Location: CARMICHAEL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A series of consecutive heavy rainfall events caused creeks and streams to rise rapidly due to ground saturation. Reports of a trailer park flooded on Sunday due to rising creek levels along Arcade Creek. Winding Way (road) was reported as flooded in low lying areas as well.

High Wind in BURNEY BASIN/EASTERN SHASTA COUNTY, CALIFORNIA
From 02-DEC-12 00:00:00 to 02-DEC-12 09:00:00 (PST-8)
Magnitude: 60.00 EG
Reported by: Trained Spotter

A series of storm systems brought heavy rain and wind to northern California. In particular, winds increased overnight late Saturday night December 1st ahead of frontal rainband that moved through...and strong winds continued into Sunday morning December 2nd. A trained spotter reported multiple trees down, including one that fell onto a house that pierced two holes in his neighbor's roof. Another fallen tree in the area took out the siding of a garage nearby. Trees were down all throughout interior northern California from strong winds and saturated grounds, blocking roadways and taking out power lines. Winds in eastern Shasta County were estimated to gust up to 60-70 mph.

Flood in BUTTE, CALIFORNIA
From 01-DEC-12 15:00:00 to 01-DEC-12 22:00:00 (PST-8)
Location: BIGGS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A series of consecutive heavy rainfall events caused creeks and streams to rise rapidly due to ground saturation. A spotter reported flooding in the Butte Sink area along the Butte and Colusa County border. Approximately 4 inches of water has accumulated over the Gridley Rd-Colusa Hwy roadway, which has closed the road.

Flood in BUTTE, CALIFORNIA
From 01-DEC-12 11:00:00 to 02-DEC-12 20:00:00 (PST-8)
Location: BIG BEND
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A series of consecutive heavy rainfall events caused local flooding due to ground saturation and steep terrain. California Highway Patrol indicated that SR70 was closed from the Jarbo Gap area to Greenville along the Feather River due to extremely heavy rains and run off from the steep terrain. Damage was reported for the roadway and possibly to the bridge. Closure began at Big Bend Road on SR70 in area indicated.

Heavy Rain in EL DORADO, CALIFORNIA
From 01-DEC-12 05:00:00 to 02-DEC-12 15:00:00 (PST-8)
Location: SHINGLE SPGS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Several series of waves containing heavy rainfall hit northern California during a high impact atmospheric river event. The last series of waves that occurred Dec. 1st and Dec. 2nd dropped an additional 1-2 inches of rainfall in the motherlode region...on top of the 4-8 inches that had already fallen previously in the first series of waves. Grounds became overly saturated, which caused trees to collapse from saturated soils and heavy absorption of water. At approximately 8 am on Dec. 4th, one oak tree fell on a vehicle that was traveling 40 mph in a Ford F-150 pickup truck on westbound Green Valley Road, approaching Ponderosa Road, killing a 48 year old man after failing to avoid the falling oak tree. The other passenger in the back of the vehicle, a 10 year old boy, was unharmed.