Low pressure formed off the coast of California and tapped into tropical moisture which lead to widespread Valley rain, mountain snow, and eventually even thunderstorm development over interior northern California. Valley rain amounts generally ranged from 0.25 to 1.0 inch of rain while foothill locations received 1.0 to 4.0 inches of rain. High elevation mountain snow was bountiful too with most sites reporting 1 to 2 feet of snow. The next day, behind the main front, widespread showers and thunderstorms developed on Nov 19.

Tornado in BUTTE, CALIFORNIA
From 18-NOV-20 13:55:00 to 18-NOV-20 14:15:00 (PST-8)
Location: BLOOMER
Tornado F-scale: EF0
Reported by: Public

A tornado was reported by multiple public sources. A chain link fence was knocked over and a few tree branches fell. No other damage has been reported. Tornado width and path is estimated.

Tornado in EL DORADO, CALIFORNIA
From 18-NOV-20 15:30:00 to 18-NOV-20 15:50:00 (PST-8)
Location: DUGAN
Tornado F-scale: EF0
Reported by: Public

A funnel cloud briefly touched down near this location with no damage reported. Location is estimated based on radar. Tornado width is also estimated.

Flash Flood in BUTTE, CALIFORNIA
From 18-NOV-20 12:31:00 to 18-NOV-20 15:15:00 (PST-8)
Location: BRUSH CREEK
Flood cause: Heavy Rain / Burn Area
Property damage: 15.00K
Crop damage: 1.00K
Reported by: County Official

A number of trees were reported down in roadways on Bald Rock Road. Significant amounts of ash and sediment were reported in roadway ditches that also overtopped the roadway in multiple locations. Timing is based on radar estimate. Location is also estimated. Damage is also estimated for debris and sediment removal, as we are unaware of any crop damage.

Flood in SHASTA, CALIFORNIA
From 18-NOV-20 10:00:00 to 18-NOV-20 12:00:00 (PST-8)
Location: ANDERSON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

California Highway Patrol reported minor flooding along Interstate 5 near Anderson, California. Time of flooding is estimated by radar. Flooding location is also estimated.

Hail in CALAVERAS, CALIFORNIA
From 18-NOV-20 16:15:00 to 18-NOV-20 16:20:00 (PST-8)
Location: VALLEY SPGS
Magnitude: 0.88 
Reported by: Trained Spotter

Nickel size hail reported near New Hogan Dam. Duration of hail is estimated.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 17-NOV-20 10:00:00 to 18-NOV-20 18:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Multiple ski resorts across the Sierra reported roughly 1 to 2 feet of snow for the event. Squaw-Alpine Ski resort reported 23 inches of storm total snow. Boreal and Soda Springs ski resorts reported 21 inches of storm total snow. Sugar Bowl reported 16 inches and Bear Valley reported 10 inches of storm total snow accumulation.

Winter Storm in WEST SLOPE NORTHERN SIERRA NEVADA, CALIFORNIA
From 17-NOV-20 10:00:00 to 18-NOV-20 18:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Caltrans reported roughly 2 to 2.5 feet of snow for the event along Interstate 80 for the higher elevations of the Sierra. Kingvale reported 17 inches of storm total snow. Donner Summit reported 27 inches of storm total snow and Soda Springs reported 26 inches of storm total snow.