A shortwave trough brought a quick round of rain and mountain snow to interior California. Snow levels for this event were generally above 4500 feet with storm total snow reports ranging between 2 and 9 inches of new accumulation.
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 shortwave trough brought a quick round of rain and mountain snow to interior California. Snow levels for this event were generally above 4500 feet with storm total snow reports ranging between 2 and 9 inches of new accumulation. This caused difficult travel conditions yet again with chain controls being hoisted and Interstate 80 holding traffic due to vehicular collisions.
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 19, 10:05 PM PST, 2 hours 55 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 1005 PM PST Fri Feb 19 2021 .SYNOPSIS... A weather system will bring a period of snow to the Sierra tonight with possible travel impacts. Thereafter, a warming and drying trend is forecast into next week with above average temperatures expected. && .DISCUSSION... The Evening Update: Adjusted the timing of the WSW to 0100 to 1000 Sat as upper low off the Nrn CA coast is forecast to take a SEly track to the SFO Bay area and then generally towards KLAS, and not a faster more Ely track. The higher REF progs indicate the snow will not overspread the Sierra zones until after midnight, albeit mostly light upslope precip may precede the forecast of heavier snow showers later this evening. C-Gs off the coast indicate the instability along the frontal band where some of the higher REF progs suggest a brief thunderstorm or two could develop in our Nrn Sac Vly/NErn foothill zones. As it were, after 9 pm a cell developed SW of Paynes Creek in zone 66 and moved rapidly NEwd with a couple pulses and a + CG strike, followed by a couple - CG strikes. The early evening convection did not occur as forecast due to a lack of diabatic destabiliztion, a timing issue. However, the vort max could trigger stronger showers, graupel showers, in addition to a flash or two of LTG after midnight. Latest Sat trends suggest the stronger dyanamics are headed towards the N SFO Bay area and then into the Srn Sac Vly and Mother Lode areas which will be in the SE to NE quadrants of the vort max, and where some of the evening REF progs suggest some higher REFs are possible. The Happy Camp snow profiler shows about a 4500 ft snow level which should approximate well with the snow level over Norcal with the frontal band later this evening. .Previous Discussion... Visible satellite imagery reveals overcast skies blanketing much of interior NorCal this afternoon. The showers from earlier in the morning have largely dissipated with only a few isolated rain/snow showers south of I-80. Total rain amounts in the Valley were between zero and 0.25 inches while foothill communities crept up to around 0.25 to 0.50 inches over the last 24 hours. In the mountains, snow amounts were generally 2 inches or less. Within the next 6-12 hours, renewed precipitation chances will return from north to south as a stronger shortwave pushes onshore. Will have to keep a close eye on radar in the northern Sacramento Valley around 4 to 9 PM PST this afternoon/evening as high resolution models depict a line of strong showers developing in portions of Shasta/Tehama Counties. MUCAPE is around 100-200 J/kg right as the energetic vort max approaches the area. Could conceivably see these strong showers develop into isolated thunderstorms east of the I-5. As a result, have added a slight chance of thunderstorms to this area this evening. As the night continues, snow will become moderate and briefly heavy at times in the mountains. Snow levels will start around 4,000 to 5,000 ft in the evening, then drop to 2,500 to 3,500 feet (locally lower in Shasta County). 4 to 8 inches of snow are expected above 4,500 feet elevation where a Winter Weather Advisory goes into effect at 6 PM PST. Not expecting snow to be falling over the course of the entire advisory (which goes through 10 AM PST Saturday), but instead travelers should anticipate periods of snow that will result in lower visibilities, slippery road conditions, and potential travel delays. Motorists are always encouraged to check with CalTrans for the updated road conditions. Precipitation will wind down tomorrow morning with gradual clearing likely by the afternoon (especially in the Valley). Highs tomorrow will max out in the upper 50s to low 60s in the Valley. For Sunday and into the first part of the new work week, upper level ridge over the eastern Pacific will allow a day-to-day warming trend with highs by Monday approaching and possibly exceeding the 70-degree mark for some Valley communities. // Rowe && .EXTENDED DISCUSSION (Tuesday THROUGH Friday)... Upper level ridge remains over the eastern Pacific on Tuesday with Valley highs in the upper 60s to low/mid 70s. Ensemble guidance flattens the ridge from Wednesday onward with temperatures moderating back by a few degrees per day. Another thing to keep an eye on will be some potentially breezy north/east winds Tuesday night to Wednesday. The Euro ENS mean 500 mb chart drops a trough into the Great Basin, which does favor offshore winds. Will have to keep a close eye as we get a bit closer for potential wind impacts. Slight chance of light precip re-enters the picture around Thursday or Friday. // Rowe && .AVIATION... Areas of MVFR with local IFR/LIFR conditions possible in precipitation as Pacific storm moves through. VFR conditions after 18Z Saturday. Surface winds generally below 12 kts at TAF sites. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 6 PM this evening to 10 AM PST Saturday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. &&
3 astronomical low tide. Local standard time, as filed.
Manzanita and Mineral reported 4 inches of storm total snow, while Chester reported 5 inches.
Caltrans reported 4 inches of storm total snow accumulation at Kingvale, 9 inches at Soda Springs, 11 inches at Donner Summit, and 4 inches of snow at Eagle Lakes . Report was completed at 0600 on February 14.
Ski resorts across the Sierra Nevada reported between 2 and 8 inches of new snow. Bear Valley received 2 inches of snow, Dodge Ridge got 3 inches, Kirkwood and Squaw/Alpine each got 5 inches, Sierra-at-Tahoe, Sugar Bowl, Soda Springs, and Boreal got 6 inches, and Tahoe DOnner got 8.
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: 945481, 945482, 945483.