A series of atmospheric river systems impacted Interior Northern California through the month of March and produced substantial flooding and wind damage.
Every event with a place to put it. Tap one for its entry below.
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 atmospheric river systems impacted Interior Northern California through the month of March and produced substantial flooding and wind damage.
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 Mar 3, 1:59 PM PST, 10 hours 1 minute earlier.
Area Forecast Discussion National Weather Service Sacramento CA 159 PM PST Fri Mar 3 2023 .SYNOPSIS... Dry weather persists today. Another strong winter storm will bring multiple feet of snow with major impacts expected once again over the foothills and mountains Saturday into early next week. && .Discussion... The calm before the storm. Visible satellite imagery reveals some passing high clouds overhead interior northern California. These high clouds are coming ahead of the incoming system that will begin impacting the region later tonight and through the weekend. For this afternoon, expect a tranquil day as most will match or exceed temperatures from yesterday with highs in the upper 50s to low 60s in the Sacramento Valley. Things start to change overnight as an upper-level low drops south along the Pacific coast toward northern California. Precipitation will begin to develop in far northwest California before sunrise, then spread south/east through the day. Initial main band of precipitation tomorrow will drop heavy snow in the mountains as well as rain the Valley. Southerly winds will increase tomorrow and be gusty through the afternoon and overnight into early Sunday. Could be a brief lull in the heaviest precipitation rates in the mountains after the the first main band progresses through the region, but this will be short-lived. Upper-level flow will become more westerly through the day on Saturday, promoting enhanced orographic lift in the Sierra Saturday night and through much of Sunday. During the heaviest snow, rates may approach as high as 2 to 3 inches per hour. Travel will become extraordinarily difficult to impossible with extended delays and closures highly probable. Conditions will deteriorate after around midnight tonight. Always check with Caltrans for the latest road conditions, restrictions, and closure information. And remember: NEVER drive beyond any road closed signs/barriers. Total new snow accumulations will be impressive. The cold-origins of this system will bring low snow levels (though not quite as low as the last storm) as well as inflated snow ratios. Snow levels around Shasta County will be around 1000 to 2000 ft and in the Sierra between 1500 to 2500 ft. For Sunday and Monday mornings, can't rule out brief periods with snow levels dropping to roughly 500 to 700 ft in the northern Sacramento Valley (i.e., Redding metro) and perhaps down to around 1000 ft in the Sierra foothills. A yard stick will be required to measure snow for many locations in the Sierra above roughly 5000 ft with areas along the Interstate 80 corridor approaching 4+ ft totals by early Monday. Combination of the wind, falling snow, and blowing snow will result in white-out conditions. While Valley communities can expect on/off periods of moderate rain during this storm, total rainfall is only expected to bring minor impacts such as slick roadways and ponding of water in low- lying areas. There is around a 10 to 20 percent chance of afternoon thunderstorms on both Saturday and Sunday afternoons, which may produce briefly heavy rainfall, small hail, and gusty/erratic winds. Total rainfall will generally range between 0.5 to 1.25 inches. This system will gradually wrap up later on Sunday or Sunday night. Continued snow showers are expected through much of Monday as another disturbance moves onshore with the long wave trough remaining over the West Coast. Additional moderate accumulations are possible through Monday and Tuesday. // Rowe && .EXTENDED DISCUSSION (Tuesday THROUGH Friday)... Trough axis will remain over the West Coast on Tuesday with snow showers expected in the mountains. Beyond the middle of next week, questions remain on *how* unsettled and what impacts come along with that. For any extended forecast analysis, it's wise to consider the range of possibilities through ensemble forecasting and cluster analysis versus traditional deterministic models which can advertise very different solutions from run-to-run. When the clusters are all advertising the same solution, there is higher confidence in the forecast. This is not the case at this point as clusters in the day 7 and day 8-10 period have varying synoptic- scale phasing/amplitude depictions. As time progresses, the forecast will inevitably evolve with a confidence eventually increasing. // Rowe && .AVIATION... VFR conditions at TAF sites over the next 24 hours. Showers spread inland from northwest to southeast after 15Z Saturday bringing local MVFR conditions. Gusty winds develop after 15Z Saturday, with southerly gusts up to 20-35 kts in the Valley and south to southwest gusts in the mountains up to 40-50 kts. Thunderstorms possible after 18Z Saturday. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 4 AM Saturday to 10 AM PST Monday for Mountains Southwestern Shasta County to Western Colusa County- Shasta Lake Area / Northern Shasta County. Winter Storm Warning from 10 AM Saturday to 10 AM PST Monday for Burney Basin / Eastern Shasta County-Motherlode-Northeast Foothills/Sacramento Valley-West Slope Northern Sierra Nevada- Western Plumas County/Lassen Park. &&
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Glenn County completed a preliminary estimate of damage from heavy rainfall and flooding. There was substantial flooding, resulting in approximately $600,000 in damage to public infrastructure, including roads, bridges and culverts.
All public entities in Tuolumne County completed a preliminary estimate of storm damage for February through April, with costs well over $42 million.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2023Every state in 2023This day in weather historyWarnings in California, March 2023
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: 1090555, 1090557.