SITUATION REPORT
Incident: Winter Weather Update

March 8-9, 2023
Published: March 8; 7:00 p.m.

KEY ISSUES/CONCERNS
Incoming Atmospheric River Weather Event Expected Thursday-Saturday: A strong
Atmospheric River weather event is expected to arrive Thursday (03/09) evening. There are two main concerns with this severe storm:
• It will come with a lot of rain, which will soak into the already deep, heavy snowpack and
make the snow on top of local roofs, propane lines and other facilities even heavier. The
public is urged to take the next 24-hours to dig out propane tanks and lines and clear roofs
as much as possible.
• It could trigger some community and street flooding when the rain hits drains and culverts
blocked by snow and ice. In lower elevation areas where the snowpack is less than a foot
deep, the rain could fully melt the snow, triggering some local flooding. Luckily, the area’s
creeks and streams are not expected to reach flood stage, according to the Reno office of
the National Weather Service, because most of the rain will be absorbed by the heavy
snowpack.

Sandbags Stationed in Each Community: Mono County and the California Office of Emergency
Services (Cal OES) are staging sandbags in each community for residents to use during the storm. Details on sandbag location information and maps for the staging areas are available here and on the READY Mono portal.

Incident Management Team (IMT) Arrives Thursday: Mono County (in coordination with Inyo
County) requested an Incident Management Team (IMT) be assigned to the Eastern Sierra to
manage the ongoing emergency. The decision to ask for the team was based on the following
reasons: the historic, deep snowpack; the fact it will take months (or longer) to fully recover from the winter’s storms; the fact there are still more storms in the forecast; and, because County staff and other resources are now fully tapped. The team will be based in Bishop due to possible road closures in Mono County.

Caltrans and CAL FIRE Crews Assisting with Snow Removal: CAL FIRE crews continue to provide snow removal in several communities. The crews are assigned to communities and facilities based on need. The Caltrans crews and equipment that arrived earlier this week to help Mono County (procured from the state due to a declared State of Emergency) continued to do snow removal throughout the county. The plan is for them to be here for two weeks, working 24-hour shifts.

WARMING CENTER AND SHELTER
Warming Center: A Warming Center has been set up in Bridgeport at Memorial Hall (73 N School Street). The center is serving three meals a day and will remain open through the coming storm and into next week. The overnight shelter that has been in place since the power went out is now closed because all displaced residents have been able to return home. Call (760) 924-4633 for more information.

Reduced Rates for Evacuees at The Carson Valley Inn: The Carson Valley Inn will be honoring a
rate of $89 plus tax in the main hotel until March 31st for anyone displaced or without power
(subject to availability). No pets. Call (800) 321-6983 for reservations.

EMERGENCY ALERTS
Winter Storm Watch: The National Weather Service (NWS) has issued a Winter Storm Watch
starting Thursday (03/09) at 4 p.m. and lasting until Sunday (03/12) at 11 a.m.

Flood Watch: The NWS has issued a Flood Watch from Thursday (03/09) at 4 p.m. until Sunday (03/12) at 11 a.m.

Mono County has declared a Local State of Emergency.
The Town of Mammoth Lakes has declared a Local State of Emergency.
Governor Newson has declared a State of Emergency for Mono County and several other
counties impacted by the storm.
The county is pursuing a federal declaration of emergency.

WEATHER CONDITIONS
An unsettled pattern of intermittent snow and sun is forecast to persist through the day Thursday before an Atmospheric River storm arrives Thursday evening. There will be 12-18 hours of heavy precipitation between Thursday evening and Friday, with the system slowly tapering off Saturday. The NWS has stated that precipitation forecast numbers have increased since yesterday’s forecast. The storm is forecast to bring 2-5 feet of heavy snow above 7,000 feet, although snow levels could also rise as high as 9,000 feet during the warmer portions of the storm. There is still some uncertainty as to how much of the precipitation will fall as rain and how much will be snow in Mammoth, but in most areas of the county, or in any areas below7,000 feet, the precipitation will be almost all rain. The updated forecast indicates the Mammoth could see up to 5 inches of precipitation, with 4 inches of that in the form of rain; Bridgeport could see about 2 inches of rain; Chalfant and the Tri-Valley area could see about 1 inch of rain.

The heavy snowpack is still expected to be able to absorb most of the rain, but flooding could
occur in areas where the snowpack is under one foot deep and in areas where drains and culverts are blocked. There is likely another storm in the forecast next week, possibly another
Atmospheric River, but it is too soon to know the details.

TRAFFIC/ROAD CONDITIONS
U.S. 395 is now open from the junction of U.S. 395 and S.R. 203 to Bishop and points south. The highway is open from the junction to Lee Vining but closed from Lee Vining to Bridgeport due to avalanches in the burned area above Mono Lake. The highway is open from Bridgeport north. There is no estimated time for opening the section of U.S. 395 north of Lee Vining where a series of avalanches took out transmission facilities and crossed the road, burying sections of the road under 30-40 feet of snow and debris. However, due to improving weather conditions today,

Caltrans was able to do avalanche control on the area and said very little snow was released,
meaning the slopes are now stable enough to consider allowing workers on the site to begin to
assess the damage and clear up. The best estimate is the road will be closed in that area for at
least this week and into next week.

S.R. 167 from U.S. 395 to the Nevada state line is closed.
Benton Crossing Road is closed.

UTILITIES
Southern California Edison (SCE) was able to energize the Lundy Power Plant and get power to
all remaining customers affected by the outages energized as of 9:30 p.m. Monday (03/06).

RESOURCES
Mono County Facebook: https://www.facebook.com/countyofmono
National Weather Service – Reno: https://www.weather.gov/reno
CHP Activity – Mono/Inyo Counties: https://cad.chp.ca.gov/Traffic.aspx
Easter Sierra Avalanche Center: https://www.esavalanche.org/

Mono County Webcams: https://www.monocounty.org/plan-your-trip/weather-and-road-
conditions/webcams-in-mono-county/

Caltrans – Road Information: https://roads.dot.ca.gov/roadscell.php