The strongest winter storm of December passed through the region on the final two days of December. This storm initially produced very high snow levels near 9000 feet on 30 December.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 REV wrote it up.
The strongest winter storm of December passed through the region on the final two days of December. This storm initially produced very high snow levels near 9000 feet on 30 December. Colder air and enhanced forcing, coupled with the final push of extensive moisture worked in unison to rapidly drop snow levels to most valley floors (above 4000 feet) during the morning of New Year's Eve. Although this early change-over to snow reduced the flooding risks, it brought widespread winter travel hazards region-wide. Storm total snow totals ranged from 5 to around 1 foot for lower elevations of western NV/northeast CA with lesser amounts below 4000 feet in west-central Nevada and areas near the Oregon border. Some foothill areas received 1-2 feet plus with Sierra snowfall totals generally ranging from 18-30 inches below 7000 feet. Higher Sierra areas and passes received 3-4 feet plus above 7000 feet. Liquid equivalent totals were impressive with 4-8 in the Tahoe basin/parts of eastern CA and over 10 near the Sierra crest. The Reno Airport’s liquid total of 2.26 on the 31st was the third wettest calendar day on record.
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 Reno, NV wrote its last area forecast discussion before the first event at Dec 30, 2:30 AM PST, 9 hours 20 minutes earlier.
Area Forecast Discussion
National Weather Service Reno NV
230 AM PST Fri Dec 30 2022
.SYNOPSIS...
This year will end with a warmer and very wet storm with the
heaviest rain and high elevation snow expected from this
afternoon through Saturday evening. Strong winds are also
expected especially on ridges, with potential flooding impacts and
significant rises on mainstem rivers. Additional colder storms
are likely next week, especially from Wednesday onward.
&&
.DISCUSSION...
A band of light snow has just exited the Basin and Range with web
cameras showing some accumulations roughly up to 1" along I-80
from Lovelock northward. Otherwise, some lighter upslope showers
continue to move across the Sierra with areas of light rain and
snow spreading into northeast CA-far northwest NV. Current snow
levels around the Tahoe basin are roughly in the 6500-7000 foot
range, but projected to rise overnight to near 9000 feet by late
morning. Sierra crest ridge gusts are already surpassing 100 mph
with the peak 700 mb flow coming later today through tonight, when
some of these exposed ridges can expect maximum gusts around 150
mph.
We'll highlight several items of the Friday-Saturday storm
here, while our multiple headline products for winter weather,
wind and floods already contain plenty of details for snow amounts
with wide variances at different elevations, along with expected
wind gusts, impacts, and actionable items.
* PRECIP TIMING/AMOUNTS/WINDS: The bulk of the moisture will come
in waves during a 24-30 hour period from late this morning
through Saturday afternoon with continuous intense rain and high
elevation snow for the Sierra and even some potential for
lightning (liquid totals 3-7" with up to 10" near the crest).
Away from the Sierra, the latest high resolution guidance is
spreading the most intense precip bands across northeast CA-
northwest NV mainly north of Pyramid Lake, although enough of
the GEFS/EPS ensemble guidance also gives a soaking for the
urban areas of far western NV (2-3" rainfall totals). Farther
south and east into Churchill, Mineral, eastern Lyon and
southeast Mono counties, precip doesn't look as intense but
still should be meaningful (0.50-1.25" rainfall totals) This
rain will be interspersed with plenty of wind-- mainly of the
advisory level speeds but some enhanced gusts could sneak
through at times, especially from this afternoon through
Saturday morning.
* COLDER SATURDAY/NEW YEAR'S EVE HAZARDS: The warm segment of this
storm is expected through late tonight. Then the transition will
begin overnight through Saturday as colder air begins to filter
southward with the main upper low moving onshore. This will be
the most complex part of the forecast as the time frame of this
transition will greatly impact the flooding potential vs. the
winter travel hazards spreading to lower elevations. The most
likely scenario indicates the greatest drop in snow levels from
Susanville-Gerlach northward through Saturday afternoon, but
falling more gradually across the Tahoe basin to near 6500-7000
feet by late afternoon. Then for Saturday evening through the
overnight hours as 2023 begins, snow levels drop to most valleys
and the heavier precip also tapers down, but some wrap-around
bands of snow or a rain-snow mix remain possible through the
early morning. We are also keeping heads up for wet roads
possibly becoming icy overnight, so be aware of changing road
conditions if you are ringing in the New Year, as the roads may
worsen as you are traveling home from celebrations early Sunday
morning.
The active storm pattern continues through the first week of
January, with storms trending colder and presenting fewer
hydrologic concerns. Widespread high-impact winter travel issues
are likely for the Sierra from midweek through next weekend, with
additional feet of snowfall, and increased snowfall impacts down
to valley floors.
Sunday into Monday AM:
* A bit of a break as the potent atmospheric river storm departs
with residual showers during the morning, then skies clear
during the afternoon and evening. Conditions will turn colder
Sunday-Sunday night, which could freeze wet roads and form
patchy black ice.
Monday PM into early Tuesday AM:
* Another fast moving storm pushes through the region Monday
afternoon and night. This storm looks to be much more modest in
terms of precip amounts and winds, and also colder with snow
down to all elevations. This quick hitting system will limit
liquid amounts to 0.10" or less for the main cities of western
Nevada and into the Basin and Range mainly north of US-50. In
the Sierra and the higher elevations of northeast California,
liquid amounts of 0.20-0.40" look likely, with 0.75 possible
along the Sierra crest. Snowfall-wise, lower elevations look to
receive less than 2", with 2-5" possible from western Lassen
County south into the Tahoe basin and western Mono County, with
up to 8" possible along the Sierra crest.
Tuesday through Thursday Night:
* We'll see another break between systems for much of Tuesday,
before a longer duration atmospheric river storm looks to affect
the region Tuesday evening through Thursday night. A couple
scenarios remain on the table for this storm--one being a single
surge of peak moisture and the other a couple rounds of moisture
surges. Ensemble guidance continues to show cold air being a
factor, with snow levels generally down to around 5000-6000 feet
during the warmest part of the storm and at valley floors for
the colder portion. Some ensemble members do show the
possibility of higher snow levels near or above 7000 feet for a
portion of Wednesday or Thursday.
Friday could bring a brief respite of dry conditions or just some
lighter snow showers, then another moderate-strong winter storm
is possible the weekend of January 7-8, with unsettled weather
possibly continuing through the second week of January. MJD
&&
.AVIATION...
Potent atmospheric river to bring a myriad of impacts to the region
as we head into the last weekend of 2022.
* As of the time of writing, winds across the Sierra crest have been
gusting over 100 mph already, with peak winds anticipated to
arrive later today. SW-W FL100 winds will be sustained 60-75 kts,
leading to strong mountain wave turbulence and wind shear
throughout the boundary layer. At the surface, gusts of 30-40+ kts
are possible at area terminals today, with lesser surface winds
tonight into Saturday due to heavy precipitation dampening the
speeds. Strong winds to continue aloft through Saturday afternoon
and evening when a cold front will shift through the region. Winds
to shift out of the N-NE behind the front Saturday evening/night.
* Rain and high elevation snow will become heavy at times tonight
through Saturday night with lowering cigs/vis and widespread
terrain obscuration. Ponding of water is expected on airport
runways. Snow levels to fall with the front Saturday late
afternoon into the evening, with light snow accumulation up to a
couple inches at KTVL/KTRK and up to 6 inches at KMMH. The snow
character will be heavy and wet. A few snow showers are possible
for KRNO/KCXP/KMEV Saturday night, but little if any accumulation
is expected.
* Flying conditions will be much improved for New Year's Day
before another fast moving system brings additional light snow
for late Monday-Monday night. Multiple additional storms are on
tap for the first week of 2023. -Dawn
&&
.HYDROLOGY...
* After our recent heavy rains, many watersheds have been primed and
will be more prone to flooding with the prolonged and heavy rain
expected Friday and Saturday. While urban and poor drainage area
flooding is likely, and probably worse than what was experienced
on Tuesday, small creeks and streams that saw significant rises on
Tuesday are likely to rise higher and maintain high flows longer.
There is a greater potential for impacts this weekend than we
experienced this past Tuesday.
* We are expecting major rises on mainstem rivers with minor to
moderate flooding possible, especially on the East Fork of the
Carson near Gardnerville, the Susan River near Susanville, and
the Pit River in Big Valley. Current guidance from the CNRFC
also has the Carson River in Carson City, the West Fork of the
Carson River at Woodfords, and the East Fork of the Carson River
at Markleeville reaching monitor stage. Uncertainty in the
timing of falling rain/snow elevations on New Year's Eve will
impact peak flows and river forecast confidence. You can find
the latest river forecast guidance at: cnrfc.noaa.gov, including
ensemble forecast data, which can aid with low probability high
impact possibilities.
* Many peak flows are expected after dark Saturday evening and
night. Nighttime flooding impacting roadways is more dangerous
due to poor visibility, and this year likely combined with New
Year's revelers. Use extra caution traveling at night, and do
not drive through flooded roadways.
-TB/Dawn
&&
.REV Watches/Warnings/Advisories...
NV...Flood Watch from 7 AM PST this morning through late Saturday
night NVZ002-003-005.
Winter Storm Warning until 4 AM PST Sunday above 7000 feet for
NVZ002.
Wind Advisory from 10 AM this morning to 4 PM PST Saturday
NVZ001.
Wind Advisory from 10 AM this morning to 4 PM PST Saturday
NVZ003.
CA...Flood Watch from 7 AM PST this morning through late Saturday
night CAZ070>073.
Winter Storm Warning from 4 AM Saturday to 4 AM PST Sunday above
6000 feet for CAZ071.
Winter Storm Warning until 4 AM PST Sunday above 7000 feet for
CAZ072.
Winter Storm Warning until 4 AM PST Sunday above 7000 feet for
CAZ073.
&&The national radar mosaic for the moment the first event began.
3 heavy rain, 2 high wind, 2 heavy snow. Local standard time, as filed.
Mesonet station (MTH03) Mammoth Mountain located 1.7 mi S of the Mammoth Mountain Ski Summit, CA, and mesonet station (DDSUM) located at Conway Summit reported maximum wind gusts of 116 mph and 82mph respectively.
The public located at the summit of Palisades Tahoe ski resort and Alpine Meadows ski resort reported maximum wind gusts of 160 mph and 152 mph respectively.
Mesonet station (LOBC1-SNOTEL) located 8.4 mi S of Walker, CA, and mesonet station (SRAC1-SNOTEL) located 2.0 mi SE of Sonora Pass, CA reported 24 hour heavy rainfall totals of 3.6 and 3.4 inches respectively during the period from 12/31/22 through 1/1/23.
The public located at Homewood Mountain Ski resort, Palisades Tahoe Ski Base, and 1.0 mi SSW of Northstar Ski Base reported storm total snowfall of 54, 47, and 46 inches respectively during the period from 12/31/22 07:00 LST through 1/1/23 07:00 LST.
The public located at Mammoth Mountain Ski base and June Mountain Ski base reported storm total snowfall of 54 and 43 inches respectively during the period from 12/31/22 through 1/1/23.
COCORAHS Station (CA-ED-20) located 2.0 mi NW of Meyers, CA, reported 24 hour heavy rainfall total of 8.32 inches during the period from 12/31/22 07:00 LST through 1/1/23 07:00 LST.
COCORAHS Station (CA-NV-51) located 2.0 mi N Truckee, CA, and CO-OP observer located 1.0 mi SSW of Boca Reservoir, CA, reported 24 hour heavy rainfall totals of 5.57 and 4.62 inches respectively during the period from 12/31/22 07:00 LST through 1/1/23 07:00 LST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, December 2022
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 2026-10-01. Each event’s entry at NCEI: 1071408, 1071409, 1071412, 1071416, 1071418, 1071421, 1071423.