A weather system brought a quick shot of winter weather to the Sierra Nevada. Reports of several inches of new snow were received.
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.
A weather system brought a quick shot of winter weather to the Sierra Nevada. Reports of several inches of new snow were received. Chain controls were in place on Interstate 80 and Highway 50 during the event. Traffic was also temporarily held to through traffic on I-80 for approximately 20 minutes early in the morning of the 9th.
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 Nov 8, 2:27 PM PST, 1 hour 33 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 227 PM PST Mon Nov 8 2021 .SYNOPSIS... The next system approaches NorCal late today through Tuesday and will bring with it widespread rain, mountain snow, and wind. Dry conditions will return by Thursday with a warming trend. && .DISCUSSION... Visible satellite imagery is showing clouds moving into Northern California this afternoon as the next weather system approaches the area. A trough associated with a parent upper low located in the Gulf of Alaska is on track to move through California tonight, bringing a quick hitting period of moderate to heavy precipitation to interior Northern California this afternoon through tomorrow. Pre-frontal, lighter precipitation will begin this afternoon over the Coastal Range and western portion of the forecast area. CAMs and HREF indicate a period of heavy precipitation is possible this evening as the surface warm front moves through the CWA. This band of precipitation is forecast to move west to east from around 8 PM to 1 AM PST. Rain rates could reach around 0.6" per hour in this band. At this point in time, rain rates are not expected to reach debris flow criteria for local burn scars, but we will be closely monitoring observed rain rates through the night. In the mountains, snow levels will actually begin lower before rising quickly overnight after the warm front passage. This evening, snow levels will begin around 4000-5000 feet in the Shasta County area and 5500-6500 feet in the Sierra and Western Plumas County, raising to above pass levels by early tomorrow morning. Still, snow rates will be around 1" per hour as the initial band of precipitation moves through the area tonight. Locations above 6000 feet could see 8-16 inches of snow, locally up to 2 feet near Lassen NP, and with lighter accumulations at lower elevations. Lighter to moderate showers will continue after the initial frontal passage through the overnight hours, becoming more isolated through tomorrow morning. There is a slight bit of elevated instability with this system, so there could be a rumble or two of thunder for areas on the western side of the CWA. Overall QPF amounts are around 0.5-1.5" in the Valley, heaviest in the northern Sacramento Valley and 0.75-3" in the foothills and mountains. Winds will also increase as the trough moves through the area tonight. Expect southerly wind gusts up to 25-35 mph in the Valley and southwesterly wind gusts up to 35-55 mph in the mountains, locally higher over ridges and wind prone areas. Ensemble guidance shows the trough moving east of the area by tomorrow evening. A trough to our north will bring warm air advection to the northern areas of the CWA on Wednesday, keeping a chance of light showers through Wednesday afternoon. Ridging will then build over the eastern Pacific Wednesday into Thursday, bringing dry conditions and temperatures warming up to near normal. Morning fog could also return to the Valley Wednesday and Thursday mornings under clear skies and light winds. -HEC && .EXTENDED DISCUSSION (Friday THROUGH Monday)... Ensembles continue in good agreement with upper level ridging bringing dry and warm weather across the area. Patchy morning fog is quite likely in the Valley with the ridge over the area bringing stable conditions, mostly clear skies and with moist ground from recent rains. Light northerly winds should limit this potential to Sacramento southward, though, and could push it to the eastern side of the Valley at times. The best potential for fog is over the northern San Joaquin Valley. High temperatures are expected to be near to slightly above normal. The next potential for precipitation arrives late Monday. A shortwave could bring some precipitation over northern portions of the area (north of I-80). The NBM is bringing pops of 30 percent over Shasta County Monday evening. EK && .AVIATION... VFR conds thru abt 03z Tue, then dtrtg conds with incrsg MVFR/IFR, lcl LIFR omtns, sprdg W to E acrs intr NorCal as nxt Pac stm movs inld. Sfc wnd incrsg aft 00z with areas Sly sust wnd up to 20 kts poss in Cntrl Vly with lcl gsts to 30 kts. SWly sfc wnd gsts up to 50 kts poss ovr hyr mtn trrn ovngt. Isold tstms poss tngt. Sn lvls arnd 3500-5000 ft AMSL aft 00z, incrsg to 5000-7000 ft AMSL ovngt. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 7 AM PST Tuesday for Western Plumas County/Lassen Park. Winter Weather Advisory until 7 AM PST Tuesday for West Slope Northern Sierra Nevada. Winter Weather Advisory until 7 AM PST Tuesday for Shasta Lake Area / Northern Shasta County. &&
3 winter storm. Local standard time, as filed.
Storm total snow accumulation reports from Sierra ski resorts reached up to 7 inches of snow.
Storm total snow accumulation of 10.4 inches was reported at Stouts Meadow in Shasta County.
Caltrans reported 1 inch of snow at their Kingvale maintenance yard, 4 inches of snow at Soda Springs, and 6 inches at Carson Pass.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2021Every state in 2021This day in weather historyWarnings in California, November 2021
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: 992224, 992230, 992232.