A series of storm systems brought unsettled weather to interior northern California from February 11 through the 14. Snow levels for these systems were above 5000 and 6000 feet which is where most of the snow fell.
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 series of storm systems brought unsettled weather to interior northern California from February 11 through the 14. Snow levels for these systems were above 5000 and 6000 feet which is where most of the snow fell. Throughout the events chain controls were periodically raised and lifted. Highway 50 and state route 89 had a hard closure at one point. I-80 and highway 50 also had temporary holds at times due to vehicular collisions. Not much data is available on timing for these events though.
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 Feb 11, 3:51 AM PST, 8 hours 9 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 351 AM PST Thu Feb 11 2021 .SYNOPSIS... A weather system will bring widespread precipitation and cooler weather today through tomorrow with another weather system following on Saturday. Mountain travel impacts are expected. Unsettled weather continues through early next week. && .DISCUSSION... Early morning satellite imagery shows upper level clouds streaming into interior Northern California as the next weather system approaches the West Coast. Widespread precipitation is on track to move through NorCal today through early tomorrow morning. Latest guidance shows precipitation moving into the north by mid to late morning, spreading southeast through the CWA through the afternoon. The heaviest precipitation is expected in the late afternoon through evening hours along the cold front, though rain rates are generally expected to remain below 0.5 inch per hour. HREF does indicate a slight chance of a few areas reaching 0.5 inch per hour tomorrow evening, but it shows no chance of rain rates above 1 inch per hour meaning no threat to recent burn areas is expected. Precipitation is expected to move out of the forecast area by early Friday morning, though a few isolated mountain showers could linger in the morning hours for areas south of I-80. QPF hasn't changed much with 0.30 to 0.75 inch of rain expected in the Valley and up to 0.75 to 2 inches in the foothills. Snow levels with this system will be 5000 to 6000 feet with the majority of the snow falling above 6000 feet. Around 6 to 12 inches are forecast at pass level with localized amounts up to 18 inches south of I-80. Mountain travel impacts are likely, especially in the late afternoon through evening hours. A Winter Weather Advisory remains in effect from noon today through 4 am Friday. This weather system will also bring cooler temperatures today. Daytime temperatures will be around 10 to 15 degrees cooler for most locations today than yesterday with Valley highs in the mid to upper 50s. Shortwave ridging is then slated to take over Friday as the upper trough moves southeast into the Desert SW. Temperatures will increase back to near 60 across the Valley which is right around normal for mid February. Ensemble guidance continues to bring in the next weather system Saturday. Overall this system remains drier than today's system, though model QPF spread remains fairly wide due to differences in the strength of the system between ensembles. Current forecast is only a few hundredths up to 0.3 inches of Valley rain with up to 0.75 inches in the foothills. Around 4 to 8 inches of snow is forecast above 5000 feet, with a light about possible down to 4500 feet as the snow levels drop Saturday afternoon. The majority of snow will fall during the day Saturday which will likely cause travel impacts over the mountains, especially since it's a weekend. The trough will move out of the area by Sunday morning, bringing another brief break in precipitation. Temperatures Saturday and Sunday will remain similar to Friday. -HEC && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Another system overspreads interior NorCal on Monday, with some lingering mountain showers possible into Tuesday. Weak forcing with this system will limit QPF despite a wide swath of deep moisture impinging on the area. Behind that, ridging expected to result in dry and milder weather through the middle of next week ahead of another system potentially lurking for the end of the week. && .AVIATION... VFR conditions thru about 18Z, then widespread MVFR with local IFR conditions develop in the Central Valley (IFR/LIFR over higher terrain) as a weather system spreads precipitation across the region. Snow level 055-065. Areas of southerly surface wind gusts 15-25 kts develop after 00Z Friday. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from noon today to 4 AM PST Friday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. &&
8 winter weather. Local standard time, as filed.
Manzanita and Mineral COOP sites reported 3 inches and 1 inch of new snow respectively.
Ski resorts across the Sierra Nevada reported between 11 and 14 inches of new snow by 9AM Feb 12. Kirkwood reported 11 inches, Sugar Bowl, Boreal, Soda Springs, and Siera-at-Tahoe reported 12 inches, and Squaw/Alpine reported 14 inches of snow.
Caltrans reported 9 inches of new snow accumulation at Kingvale, 10 inches at Soda Springs, 12 inches at Donner Summit, and 5 inches of snow at Eagle Lakes.
Chester and Mineral reported 1 inch of snow accumulation each, while Manzanita reported 7 inches of snow.
Ski resorts across the Sierra Nevada reported between 2 and 9 inches of new snow by 8AM Feb 13. Dodge Ridge received 2 inches of snow, Kirkwood got 3 inches, Sierra-at-Tahoe and Squaw/Alpine each got 6 inches, Bear Valley received 8 inches, and Sugar Bowl and Soda Springs got 9 inches.
Caltrans reported 9 inches of storm total snow accumulation at Kingvale, 15 inches at Soda Springs, 16 inches at Donner Summit, and 7 inches of snow at Eagle Lakes . Report was completed at 0600 on February 14.
The Mineral COOP site reported 2 inches of new snow.
Caltrans reported 1 inch of new snow accumulation at Kingvale, 6 inches at Soda Springs and Donner Summit.
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, February 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: 945473, 945474, 945475, 945476, 945477, 945478, 945479, 945480.