Northern California typically experiences a wet season, October through May, and a dry season May through September. Last year's water year, October 2019 through September 2020, was one of the driest on records.
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.
Northern California typically experiences a wet season, October through May, and a dry season May through September. Last year's water year, October 2019 through September 2020, was one of the driest on records. This likely contributed to the U.S. Drought Monitor's decision to place portions of interior northern California into extreme drought on September 29, 2020. Portions of Shasta, Tehama, Butte, Glenn, Colusa, Yolo, Solano, Yuba, Nevada, and Sacramento counties remain placed extreme drought. The rest of interior northern California was placed into severe drought (D2) on December 8; however, the state of California has not announced that these locations are in drought.
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 31, 10:20 PM PST, 1 hour 40 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 1020 PM PST Thu Dec 31 2020 .SYNOPSIS... Dry weather is expected across the region today and New Year's with fog development possible tonight into tomorrow morning. Another weak system will bring a chance of rain and mountain snow on Friday night into Saturday before the pattern becomes more active Sunday into next week. && .DISCUSSION... The Evening Update: Skies mostly clear, other than some high clouds drifting S over Norcal this evening, as the ridge axis along the W Coast drifts inland. Northerly winds from high pressure lowered the dewpoints over the region, but the winds should decrease later this evening as the lower atmosphere decouples. With light Sly winds returning over the Srn portion of the Vly, the HREF suggests some IFR wx will return to the Nrn SJV and Srn Sac Vly by/after 12z as moisture slowly recovers. Weekend wx system progged to stay mainly N of the I-80 corridor, with more significant precip holding off until Mon. We may have to re-adjust the timing of our WSW product in later forecasts. JHM Previous Discussion... Visible satellite shows mostly clear skies over interior Northern California this afternoon with a few upper level clouds over the northern counties. Upper level ridging is building over California early this afternoon which is creating locally gusty north to east winds. Generally gusts up to 20 to 30 mph will continue through the afternoon, weakening in the evening hours. Light winds overnight will allow for Valley fog formation tonight into tomorrow morning, especially in the southern Sacramento Valley and northern San Joaquin Valley. Dry weather is expected through most of the day tomorrow before a weak weather system makes it's way through the area tomorrow night through Saturday morning. Mostly light precipitation is forecast with this system with the majority remaining north of Highway 50. The upper level flow flattens out over California Saturday into Sunday. Warm air advection with enough moisture flow could allow scattered showers to linger Saturday into Sunday. Best chances of precipitation will be over the mountains and foothills north of Highway 50. Precipitation amounts of half an inch to an inch and a half are possible Friday night through Sunday over the foothills and most of Shasta County except for the Burney Basin area in eastern Shasta County. Elsewhere, precipitation amounts are expected to be around a few hundredths to a quarter of an inch. Snow amounts will remain fairly light at pass level, generally around a couple of inches, with local amounts up to 5 to 10 inches over Lassen Park. The next weather system approaches the west coast later Sunday. This is expected to be a stronger storm that is expected to begin impacting interior NorCal late Sunday night. More details below. -HEC && .EXTENDED DISCUSSION (Monday THROUGH Thursday)... Winter storm will likely affect the area Monday and a winter storm watch has been issued. Some model timing differences remain with this system, as the GFS depicts an upper low moving across the Northern Sacramento Valley Monday evening, while the Euro has a more progressive trough pattern. GFS solution is heavier with precip and would keep it going through Monday night while Euro would taper things earlier. In any event expect a significant winter storm, especially at pass level and above. The heaviest snow is expected for elevations above 5500 feet with light accumulation possible down to 4500 feet late Monday night. Hazardous mountain travel conditions are anticipated with this storm. Total snow accumulations of 8 to 18 inches, with localized amounts up to 2 to 3 feet at higher peaks, are possible. Active pattern continues next week with another significant storm system possible around Wednesday. Changes in timing and strength are still possible, so the main takeaway for the extended period should be that there will be periods of hazardous mountain travel early next week and possibly multiple feet of snow by mid-week. In the Valley, expect periods of rain showers with some breaks in the precipitation. If traveling in the mountains, pay close attention to the forecast and adjust plans appropriately. && .AVIATION... Wind gusts to 25 mph possible over the Southern Sacramento and Northern San Joaquin Valleys through 00z. Winds will diminish to less than 10 mph overnight. Fog formation possible late night and early Fri morning hours, although confidence is low given possible drying from afternoon north winds. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Sunday evening through Monday evening for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. &&
5 drought. Local standard time, as filed.
For the month of January, the U.S. Drought Monitor kept the majority of zone 13, which covers Shasta County, in extreme drought (D3). The California Department of Water Resources continues the water allocation of 10% for the State Water Project that started on December 1st.
For the month of January, the U.S. Drought Monitor kept all of zone 15, portions of Shasta and Tehama counties, into extreme drought (D3).They also noted on this month's call the following impacts for the Sacramento Valley: low groundwater levels, dry stock pond, and poor range-land and pasture conditions. Some ranchers have even stated they've started selling livestock. Additionally, the California Department of Water Resources continues the water allocation of 10% for the State Water Project that started on December 1st.
For the month of January, the U.S. Drought Monitor kept most of Glenn and Colusa, and Sutter counties along with the western portions of Butte and Yuba counties in extreme drought (D3). They also noted on this month's call the following impacts for the Sacramento Valley: low groundwater levels, dry stock pond, and poor range-land and pasture conditions. Some ranchers have even stated they've started selling livestock. Additionally, the California Department of Water Resources continues the water allocation of 10% for the State Water Project that started on December 1st.
For the month of January, the U.S. Drought Monitor kept all of Yolo County, and portions of Sacramento, Sutter, Solano counties in extreme drought (D3). They also noted on this month's call the following impacts for the Sacramento Valley: low groundwater levels, dry stock pond, and poor range-land and pasture conditions. Some ranchers have even stated they've started selling livestock. Additionally, the California Department of Water Resources continues the water allocation of 10% for the State Water Project that started on December 1st.
For the month of January, the U.S. Drought Monitor kept all of zone 63, which covers western Tehama, Glenn, and Colusa counties in extreme drought (D3). They also noted on this month's call the following impacts for the Sacramento Valley: low groundwater levels, dry stock pond, and poor range-land and pasture conditions. Some ranchers have even stated they've started selling livestock. Additionally, the California Department of Water Resources continues the water allocation of 10% for the State Water Project that started on December 1st.
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, January 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: 938994, 938995, 938996, 938997, 938998.