A low pressure system from the Pacific northwest dropped through the region bringing showers and thunderstorms, with up to 7 inches of new snow over the Sierra.
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 low pressure system from the Pacific northwest dropped through the region bringing showers and thunderstorms, with up to 7 inches of new snow over the Sierra.
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 May 6, 8:10 PM PST, 3 hours 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 910 PM PDT Wed May 6 2015 .Synopsis... Low pressure dropping southward from the Pacific Northwest will bring a chance for showers and thunderstorms, mainly to the mountains through the end of the week. Near normal temperatures through the end of the week...then warming over the weekend. Breezy north winds tonight and Thursday mainly on the West side of the Valley. Chance of showers or thunderstorms again early next week mainly northern mountains. && .Discussion (Today through Saturday)... There are still some showers and isolated thunderstorms late this evening but in general over the next few hours expect just some isolated activity to occur. As the low shifts southward after midnight and into Thursday morning that's when the models increase the activity over the interior and mountains. This is also the best time period for the valley to see any showers from this system. The central part of the low drops down over the central coast in the afternoon with models indicating showers likely over the mountains and mainly dry conditions for the valley. Snow levels may drop down to around 5000 feet Thursday morning but not much in the way of snow is expected at that level or any for that matter during this time period. Better accumulations will be above 7500 feet but a couple of inches down to around 6500 feet look possible in the afternoon and evening and mainly from around Plumas county southward. The higher total look to occur around highway 88 and to the south. The low will continue to shift southward on Friday but wrap around moisture from the low will continue chances for showers and thunderstorms over the Sierra Nevada. Snow levels rise well above pass levels to around 8000 feet or higher during the day. By Saturday the low pressure will have moved well to the southeast of the area. Models are trying to indicate some isolated afternoon activity possible along the crest south of Tahoe...otherwise expect dry conditions and slightly warmer temperatures. .Extended Discussion (Sunday through Wednesday) Medium range models showing weak upper ridging over the forecast area Sunday with just a slight chance of afternoon showers or thunderstorms over the Coastal range and Shasta mountains. Another upper low is then forecast to dig south along the NW Cal coast Monday, swinging inland over Interior NorCal Tuesday. Models then differ significantly on how quickly to eject the low eastward Wednesday. Potential for showers and thunderstorms exist early next week with Tuesday expected to be the most active day. Cooling trend forecast with highs near normal by Tuesday. && .Aviation... Upr low digs S thru Intr NorCal nxt 24 hrs with mnly VFR conds exc lcl MVFR poss in shwrs or tstms omtns. Lcl Nly sfc wnd gsts to 30 kts dvlpg ovr Intr NorCal tngt into Thu mrng contg into Thu eve. && .STO Watches/Warnings/Advisories... winter weather advisory from 5 am thursday to 5 am pdt friday west slope northern sierra nevada. &&
1 winter weather. Local standard time, as filed.
Snow caused slippery roads on mountains and passes above 6500 feet, with 7 inches of snow measured 3W of Shriner Lake Campground. This impacted mountain roads from Highway 50 southward, including Echo Summit on Highway 50, Carson Pass on Highway 88, Ebbetts Pass on Highway 4, and Sonora Pass on Highway 104.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2015Every state in 2015This day in weather historyWarnings in California, May 2015
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: 581865.