Yet another atmospheric river brought heavy rain and snow to the Sierra Nevada and the Owens Valley on the 9th and 10th. Flooding persisted for several days after.
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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 VEF wrote it up.
Yet another atmospheric river brought heavy rain and snow to the Sierra Nevada and the Owens Valley on the 9th and 10th. Flooding persisted for several days after.
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 Las Vegas, NV wrote its last area forecast discussion before the first event at Mar 9, 2:50 AM PST, 11 hours 10 minutes earlier.
Area Forecast Discussion National Weather Service Las Vegas NV 250 AM PST Thu Mar 9 2023 .SYNOPSIS...Increasing rain and high elevation snow chances arrive in the Sierra and Owens Valley by late this afternoon. Shower chances will spread eastward tomorrow but chances remain slim outside of the higher mountain terrain and Spring Mountains. Gusty conditions are expected Friday as well. Drier conditions resume over the weekend but additional storm systems will arrive next week. && .SHORT TERM...through Friday night. Changes are afoot this morning as a rather powerful atmopsheric river takes aim at the California coast. Early morning satellite imagery depicts deep subtropical moisture already in position off the central California coast, with a rich moisture tap extending back to the Hawaiian Islands. Radar echoes are already on the increase off the coastal waters, and this plume of moisture will begin to creep inland through the morning, and reach our eastern Sierra zones by mid-afternoon. Confidence remains high on a significant precipitation event across the Sierra, with rising snow levels. Confidence decreases heading downslope into the Owens Valley with regards to precipitation amounts, as high resolution guidance continues to suggest a rather strong rainshadowing from the US-395 corridor eastward, and this makes sense given the stronger dynamic forcing will be focused further north across Northern California and the Great Basin. However, precipitable water values will be at record levels for mid-March and snow levels will be climbing into the 8000-9000 foot range by Friday morning. So given the existing snowpack in parts of the Owens Valley, relatively warm rain falling on melting snow (especially west of US-395), and potential for at least brief periods of enhanced rain rates, the flood risk remains regardless of exactly how much rain falls. Even further east, high resolution guidance has trended upward with precipitation chances in the Spring Mountains late tonight into Friday. This is where fairly strong moisture transport entrained in the westerly flow will be forced upslope and effectively "wrung out" over the terrain barrier. Snow levels will be quite high, climbing above 9000 feet for the duration of the rain chances, so winter impacts will be minimal. However, some of the snowpack below the 7000 foot level could see an accelerated rate of snowmelt that could lead to enhanced streamflows in the area. Outside of the above mentioned areas, not expecting much in the way of precipitation impacts. While the atmospheric profile will be quite moist Friday, this is largely just deep subtropical moisture entrained in the jetstream that is lacking any larger scale forcing to produce appreciable rainfall. So while clouds will be abundant on Friday, most areas will struggle to see much more than sprinkles. Outside of the precipitation concerns, winds will be on the increase Friday as well. Abudnant cloud cover could reduce the mixing potential slightly, but winds gusts of 35 to 50 mph will be common regardless across much of the Mojave Desert and Arizona Strip. Gusty west winds may also surface in the Owens Valley, epsecially south of Owens Lake and impact travelers on the US-395 corridor. Given these concerns, posted a wind advisory for Friday for the above mentioned areas. Strongest winds around the Las Vegas Valley will be on the western and southern sides of town where downslope winds off the Spring Mountains will be strongest. .LONG TERM...Saturday through Wednesday. By Saturday morning, the low pressure system which helped direct the atmospheric river into the Sierra will have moved away into the northern Plains, and the AR will be winding down, with only light precip persisting in the Sierra and southern Great Basin. Gusty west to southwest winds will persist in the Mojave Desert for one more day before settling down Saturday night into Sunday morning. Zonal flow/flat ridging should bring generally dry weather Sunday with high clouds passing by, and above normal temperatures. The long-awaited warmth could be as much curse as blessing, as melting snow will continue to swell creeks and rivers. By Monday, the next AR is forecast to be dumping on the Pacific Northwest, and the main forecast challenges for our area are when it gets directed this far south and how long it sticks around. Tuesday is the model consensus for the best chance of another round of significant precip in the Sierra, with snow levels somewhat lower (6000 to 7000 feet) than with the first AR. Upper level troughing is forecast to pass by to the north on Tuesday, not only focusing the AR into the Sierra, but also potentially bringing enough forcing to allow light precip to spill over into the deserts. There is significant model spread with another storm system immediately on the heels of the Tuesday one. Some solutions bring another round of precip to much of the area, heaviest in the Sierra, Wednesday and Wednesday night; others take the trailing system so far south that precip is limited to areas southeast of I-15. At this time, the biggest takeaways should be that the snowpack will continue to melt, possibly causing flooding issues in the typical places, and another round of rain and snow looks like a decent bet for Tuesday. There is some potential for another storm Wednesday, but lots and lots of uncertainty associated with it. Details should become clearer as we get closer. && .AVIATION...For Harry Reid...Light winds of less than 10kts will continue into this evening. Initially, winds will favor a southwesterly direction, but a gradual shift to the southeast is likely by mid-day. Winds will return to a southwesterly direction by early evening. Speeds will increase overnight, and southerly winds with occasional gusts over 25kts are likely by Friday morning. No operationally significant cloud cover is expected through this evening. However, clouds will thicken, and bases will lower to around 6kft by Friday morning and remain in place through Friday evening. For the rest of southern Nevada, northwest Arizona and southeast California...Light south to southwest winds of generally 10kts or less can be expected across southern Nevada and the Colorado River Valley today. At KDAG, light westerly winds will continue into the evening before increasing to around 15kts overnight. At KBIH, light northerly winds will turn southerly this afternoon, and light rain is expected after 02Z but will likely become more scattered and showery overnight. All TAF sites, except KBIH, will see SCT to BKN mid and high clouds through the forecast period. CIGs at KBIH will lower to around 3kft by this evening and could go as low as 2kft in any areas of heavier precipitation overnight. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && SHORT TERM...Outler LONG TERM...Morgan AVIATION...Planz For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter
The national radar mosaic for the moment the first event began.
1 heavy snow, 1 flood, 1 avalanche. Local standard time, as filed.
Thirty inches of new snow fell at Aspendell.
Heavy rain and melting snow resulted in a mix of flooding and flash flooding throughout the Owens Valley. Highway 395 and nearby roads were flooded in areas from 15 miles NW of Bishop all the way down to Pearsonville. Several roads were flooded with water, rocks, and/or debris, and a few vehicles were stuck. Southern Inyo Hospital in Lone Pine was flooded. The Los Angeles Aqueduct failed in multiple areas, resulting in one dam failing and flooding open desert, as well as flooding of Highway 136 due to releases from Alabama Gates.
Several small avalanches occurred near Habegger Lane 2 miles E of Aspendell.
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: 1089496, 1089494, 1089495.