Strong storms developed behind a cold front, bringing abundant rain and severe weather, including a damaging micro-burst and large hail in the foothills.
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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.
Strong storms developed behind a cold front, bringing abundant rain and severe weather, including a damaging micro-burst and large hail in the foothills.
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 21, 3:41 AM PST, 4 hours 49 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 441 AM PDT Tue Mar 21 2017 .Synopsis... A series of weather systems will bring cooler and more unsettled weather to the region this week. Chance of thunderstorms today with gusty winds and small hail. && .Discussion... Upper trough centered off the West Coast with surface cold front approaching the NorCal coast early this morning. Plenty of showers continue across the region with breezy southerly winds and mild temperatures. Current temperatures are in the upper 30s and 40s in the mountains with 50s elsewhere. Mild airmass lies across the region ahead of the front with radar profilers indicating the snow level is generally around 7-8K feet. Precipitation fell as snow earlier in the night over Donner Pass but has changed back to rain, so little to no travel impacts are expected until around midday when cooler air will begin to make it into the northern Sierra. Primary weather concern for today will be extent and severity of deep convection expected to develop in the Central Valley during the midday hours as the short-wave (now inside 130W) moves onshore. Still lots of questions to whether we'll see a whole lot of clearing this morning allowing for greater destabilization of the boundary layer. High-res models continue to point toward the 18Z-22Z time-frame as most likely for thunderstorm development from Butte County southward. They also quickly evolve cells to the north of Sacramento into more linear orientation while maintaining more discrete cells across the northern San Joaquin Valley. Primary concern with stronger storms will be copius amounts of small hail along with gusty winds though a brief tornado or two cannot be ruled out, especially over the northern San Joaquin Valley where it looks like the best combo of instability and low-level shear will be present. We'll continue to monitor. Showery precip continues tonight and Wednesday as the upper trough moves overhead. Snow will continue in the mountains with snow levels lowering to 4-5K feet. There may be some travel impacts at times through the passes as around 3-6 inches of snowfall accumulation is expected for Donner Pass and Echo Summit. Short-wave ridging briefly builds in for Thursday with a break in precipitation across most of the area and a bit of sunshine ahead of the next approaching system for the end of the week! && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday) Stormy pattern expected to continue next weekend as an upper trough slides across the region. Temperatures will be about 5 to 10 degrees below normal with Valley rain and snow for elevations above 3500 feet. An upper level ridge will build on Monday, which will bring a return of mostly dry weather for the valley and warming temperatures. Chances for rain are possible Monday for the higher terrain. && .AVIATION... More widespread precipitation is expected today with increasing MVFR/IFR conditions, and southerly winds with gusts 20 to 30 knots in the valley after 12z. These conditions will continue through this afternoon with chances for thunderstorms. VFR conditions expected beyond the late afternoon. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from midnight tonight to 6 PM PDT Wednesday for Western Plumas County/Lassen Park. Winter Weather Advisory until 6 PM PDT Wednesday for West Slope Northern Sierra Nevada. &&
The Sacramento radar (KDAX), 17 km away, was scanning. The volume nearest the first event began at 16:30 UTC.
9 flood, 3 funnel cloud, 1 heavy rain, 1 lightning, 1 thunderstorm wind, 1 hail. Local standard time, as filed.
Very heavy rain with standing water was reported on roads in South Sacramento, including on Highway 99.
Roadway flooding reported in eastern Sacramento at Folsom Blvd and 47th St.
CHP reported flooding on on-ramp to SR 51 by Auburn Blvd. Standing water in lane, bottom of the cloverleaf was flooded.
Ethel Way was flooded between Fruitridge Rd. and 28th Ave., Sacramento.
CHP reported roadway flooding at Fulton Ave and Arden Way, Sacramento.
CHP reported roadway flooding at US 50E and 34th Street off-ramp.
Roadway flooding reported by CHP at Watt Ave. and Arden Way, Sacramento.
Roadway flooding reported by CHP at Exposition and Response Rd., Sacramento.
More than half an inch of rain fell within 15 minutes, flooding roadway at Madison Ave. and I80. Lots of freeway spin-outs.
Flooded roadways reported in Tahoe Park, Sacramento.
Lightning hit a tree in Oakdale, CA, causing a fire in nearby electrical transformer and resulting in a power outage. Three homes and a few vehicles were reported damaged.
Trained spotter reported 2 brief funnel clouds north of Turlock. No touchdown reported.
Funnel cloud reported briefly visible from West Linwood Ave., Turlock, CA.
An NWS storm survey team determined straight line winds from a micro-burst associated with a severe thunderstorm caused damage in Twain Harte, CA Numerous trees were brought down, and a home was damaged. Winds gusted to an estimated 105 mpg. Significant wind damage was done along Twain Harte Rd. with many trees and power lines knocked down as a severe thunderstorm passed through. A woman was briefly trapped in a damaged vehicle by a falling tree, and was rescued by the fire department. The woman was not injured.
A photo on Twitter showed large hail in Groveland, estimated to be 1.25 in diameter.
A funnel cloud was briefly spotted west of Rocklin. No touchdown was observed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2017Every state in 2017This day in weather historyWarnings in California, March 2017
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: 685615, 685617, 685619, 685623, 685627, 685630, 685631, 685636, 685639, 685626, 685647, 685643, 685641, 685662, 687143, 685613.