Heavy rain brought ponding of water on area roads. Mountain snow caused chain controls and delays on Sierra passes.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS STO wrote it up.
Heavy rain brought ponding of water on area roads. Mountain snow caused chain controls and delays on Sierra passes.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at Dec 15, 1:36 PM PST, 10 hours 24 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 136 PM PST Sat Dec 15 2018 .SYNOPSIS... A moderate storm system will track over NorCal Sunday into Monday with hazardous mountain travel likely. Dry weather returns for much of next week. && .DISCUSSION... A few light showers remain ahead of the next weather system due in tomorrow. Enough moisture and uplift, mainly over mountains may linger overnight to continue to produce some showers. The weather system will start to move onto the coastal range in the morning but its the afternoon when the front moves closer to the region and upslope areas start to get enhanced precipitation. The front will move through the Sacramento area during the late afternoon to early evening hours. Snowfall will be increasing near major pass levels at this time. Have put out an Advisory for the Western Plumas County/Lassen Park with a Winter storm warning for the West Slopes Northern Sierra Nevada. Snow levels stay high enough over the far north to lower snowfall totals over the populated areas/roads traveled. Lassen Peak could see up to 2 feet of snow. The snow levels further south look to be near pass level for the afternoon into the early evening before lowering. The higher totals will be above 6500 feet where up to a foot of snowfall could accumulate below pass levels. The heaviest snowfall looks to occur from mid to late Sunday evening trough 8 AM Monday morning gradually tapering from north to south after 3 AM. Breezy conditions are likely as the front moves through for most of the area outside of the crest which will be its normal windy conditions for winter storms probably in the 50 to 75 mph range over the peaks. For the valley a half inch to an inch an a half of rain can be expected with the highest totals over the north end of the valley tapering to lowest in the Northern San Joaquin Valley. The main part of the system clears the region early Monday morning with some residual showers lingering mainly over the mountains during the day before ending in the southern forecast areas. Weak ridging tries to build but a tail end of a system moving into the Pacific Northwest will pass through the far northern part of the state to keep some chances of precipitation going through Tuesday.(Mainly north of Chico in the valley and well north of I-80 for the Mountains) To the south expect to stay dry. && .EXTENDED DISCUSSION (Wednesday THROUGH Saturday) Forecast confidence is low for late next week as models are currently inconsistent from run to run. Overall model setup has a ridge building and remaining over NorCal Wednesday through Thursday. Then models bring a weak upper level trough over the west coast Thursday night through Friday. The precipitation chances over NorCal with this system depend on how deep the trough digs. Current model runs deepen it enough to bring light precipitation over the northern Valley and mountains, mainly north of I80. Impacts are currently expected to remain low with this system. HEC && .AVIATION... Widespread MVFR/IFR conditions likely to continue north of KMYV next 24 hours as warm-advection continues to result in low ceilings. Elsewhere, VFR conditions expected to predominate with areas of MVFR and local IFR visibilities in the Central Valley after 8Z Sunday. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 2 PM Sunday to 8 AM PST Monday for Western Plumas County/Lassen Park. Winter Storm Warning from 2 PM Sunday to noon PST Monday for West Slope Northern Sierra Nevada. &&
The national radar mosaic for the moment the first event began.
2 heavy rain, 1 winter weather. Local standard time, as filed.
Downtown Sacramento set a daily record for rainfall, 1.17 inches of rain, breaking the old record of 0.95 inches set in 2002.
Red Bluff set a daily record for rainfall, 1.77 inches of rain, breaking the old record of 1.25 inches set in 1962.
There were chain controls in place on Interstate 80, Highway 50, State Route 4 (SR-4) in Calaveras County and Alpine County, SR-88 in Amador and Alpine counties and SR-108 in Tuolumne County. Snow amounts reported were 8 inches at Dodge Ridge, 6 inches at Castle Peak, 5 inches at Donner Ski Ranch, and 4 inches at Sugar Bowl.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2018Every state in 2018This day in weather historyWarnings in California, December 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 798642, 798643, 798659.