Nevada, 2023Debris Flows and Avalanche in Nevada, March 9 to 12, 2023
March 9 to 12, 2023 · NWS REV · 20 events in 9 counties and zones
Strong, even damaging west-southwest winds increased travel hazards especially to high profile trucks but also increased the danger for destructive avalanches across the region. Snow started at all elevations Thursday evening with snow levels rapidly rising Friday morning.
Every event with a place to put it; 6 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
Open the live radar over this ground
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 20
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.
Strong, even damaging west-southwest winds increased travel hazards especially to high profile trucks but also increased the danger for destructive avalanches across the region. Snow started at all elevations Thursday evening with snow levels rapidly rising Friday morning. Heavy, wet snow (Sierra Nevada Cement) fell across higher elevation areas as snow levels rose to 7000 feet over the region. Heavy rainfall increased the possibility of flooding for lower elevation creeks, streams, along with urban drainage issues due to snow berms. Significant rises on mainstem rivers were monitored for flooding. Deep, cold snowpack absorbed most liquid precipitation during this second AR supported storm system.
What forecasters said that day
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 Mar 8, 3:10 PM PST, 11 hours 50 minutes earlier.
Area forecast discussion, Mar 8, 3:10 PM PST, 11 hours 50 minutes before
Area Forecast Discussion
National Weather Service Reno NV
310 PM PST Wed Mar 8 2023
.SYNOPSIS...
After a short break in storm activity through Thursday morning, a
potent atmospheric river storm will bring rising snow levels with
strong winds, heavy mountain snow and lower elevation rain
Thursday afternoon through Friday, with possible flooding in poor
drainage areas. Additional waves of moisture will keep rain and
snow chances going at times from this weekend into next week.
&&
.DISCUSSION...
Some bands of light snow showers will linger into the evening
across parts of western Nevada along the I-80 corridor to the
north and south to Highway 50. Snow accumulations will remain
generally light with only minor impacts for roads already cleared
of snow. Breezy conditions accompanying the short wave trough
passage, along with areas of blowing dust across the Basin and
Range north of I-80 and east of Highway 95 will begin to diminish
into the evening. A quick moving short wave ridge will then bring
a brief period of clearing overnight into Thursday morning before
the next winter system moves into the region later in the
afternoon. -Amanda
A very active and impactful weather pattern for the upcoming week
will be highlighted by a surge of atmospheric river moisture
accompanied by a 150 kt subtropical jet headed directly into the
Sierra starting Thursday afternoon, then spreading across western
NV. Peak precip rates, wind speeds and impacts are expected
Thursday evening through Friday afternoon. Additional waves of
moisture, although not as intense or warm, are projected to
continue through the weekend.
Highlights for the first storm from Thursday night through the
weekend:
* WINDS: 700 mb flow of 60-70 kt, with jet stream level flow of
120-130 kt over the Sierra, will bring strong and potentially
damaging winds late Thursday evening through Friday evening. The
peak gusts are likely to reach western NV during the day Friday.
Even with some dampening of the wind speeds with precip
occurring, wind gusts of 60-70 mph remain possible at times,
with Sierra ridge gusts surpassing 120 mph.
* PRECIP AMOUNTS: Impressive precipitation totals are projected
from Thursday afternoon through Saturday night, with recent
guidance indicating 6-9" of liquid equivalent along the Sierra
crest, 3-6" in Sierra communities, 1-2" along US-395 from
northeast CA to the main urban areas of far western Nevada, 2-4"
for foothill areas mainly west of US-395, and 0.25-0.5" for the
west central NV Basin & Range. The latter portion of the
weekend could bring another 0.50" liquid to the Tahoe area with
around 1" near the Sierra crest, but western NV likely becomes
more shadowed out with minimal additional rainfall through
Sunday. These precip amounts will be capable of producing
flooding concerns--see the hydrology segment for additional
details.
* SNOW LEVELS/AMOUNTS: This continues to be the wild card as snow
levels start rather low (near 4500-5500 feet) with the initial
moisture push Thursday afternoon. The most likely scenario
raises snow levels quickly through Thursday evening-night to
near 8000-8500 feet. While more intense precip could
occasionally lower snow levels by 1000-1500 feet, the majority
of precip below 7500-8000 feet will most likely fall as rain or
a rain-snow mix until some cooling arrives Friday afternoon-
night. Snow levels then look to dip to 5000-6000 feet by early
Saturday for Tahoe and western NV between I-80 and US-50, near
7000 feet for Mono County and western NV south of US-50, but
fall down to near 4000 feet for northeast CA-far northwest NV
where the colder air mass makes more progress. The cold front
then stalls and lift northward before becoming more poorly
defined during the remainder of the weekend, with resultant snow
levels generally around 5500-6000 feet north of I-80 and
6000-7000 feet from I-80 southward. Snow amounts for the Sierra
will vary quite widely by elevation but with expectations for
several feet in the higher elevation sites, the watches for the
eastern Sierra/Tahoe area will be upgraded to Winter Storm
Warnings--see our latest statement for more details on potential
snowfall amounts. For the main western NV urban areas, this
event will be nearly all rain, with a few foothill sites above
5000-5500 feet maybe receiving up to an inch or so of snow at
the onset (Thursday evening) and the tail end (early AM
Saturday) of the main storm.
For early-mid next week, the Sierra may not see much of a break as
upslope snow showers continue Sunday night-Monday. Then another
colder storm system moves through with a round of moderate-heavy
snow Monday night into Tuesday. Even beyond that, another fast
moving storm is on track for midweek. While these storms currently
appear to be colder compared to the Thursday-Saturday event and
reduce the overall flood risk, the tracks still could vary and
bring a period of higher snow levels. However, the colder storm
scenario would further compound the winter impacts for areas
already overwhelmed by excessive season-long snowfall, including
the new snow coming prior to next week. For lower elevations of
western NV, significant snowfall isn't likely, but short bursts
of snow could produce some travel impacts for the Tuesday and
Wednesday morning commutes. MJD
&&
.AVIATION...
* Some light snow showers will linger in the vicinity of Sierra
terminals with bands of light snow showers diminishing across
western Nevada going into the evening. A lingering light snow
shower or two may briefly bring MVFR/IFR conditions in CIG/VIS
for KLOL and KNFL. For the most part VFR conditions will prevail
for western Nevada terminals overnight through Thursday morning.
Later Thursday morning, snow shower chances will begin to
increase across northeast California, which will spread periods
of IFR conditions east and south towards Sierra terminals (KSVE-
KTRK-KTVL) Thursday afternoon.
* Moderate turbulence and LLWS will subside briefly overnight but
begin to increase once more late Thursday morning as Sierra
ridgetop wind gusts surge to 90 kts. FL100 winds will also
increase to 50-60 kts by 00Z Friday as well. Sierra terminals
will see southwest wind gusts increasing to 20-30 kt Thursday
afternoon and evening, with western Nevada terminals seeing
wind gusts to 25 kts.
* Latest model scenarios continue to show a very active pattern
starting Thursday night though Saturday and a followup lower
confidence storm Monday through Wednesday next week. Aviators
should expect periods of strong winds and turbulence, along with
heavy precipitation to impact the region Thursday night-Saturday
and again Monday to Wednesday next week. -Amanda
&&
.AVALANCHE WEATHER...
High confidence for a strong atmospheric river storm Thursday
night through Saturday, producing very heavy precipitation with
variable snow levels and significant impacts for avalanche
concerns.
* 24-hr Snow Water Equivalent (SWE): High-end SWE of 3-6" along
the crest from Thursday evening through Friday afternoon, with
hourly rates of 0.25-0.50" at times during peak intensity. SWE
rates decrease by Friday night but additional 1-3" possible
through the weekend.
* Snow-Liquid Ratios: Lower snow-liquid ratios of 7-10 to 1,
except 10-13 to 1 for the Sierra crest above 9000 ft through
Friday. Cooler air will increase snow-liquid ratios to 10-14 to
1 for Friday night-Saturday morning.
* Winds: Strong southwest winds expected with gusts to 100-125
mph across the ridges Thursday afternoon through Saturday
morning.
Active pattern will continue through the middle of next week with
the highest probability for more impactful snow and wind Monday
night-Wednesday. MJD
&&
.HYDROLOGY...
Bottom Line: Increasing confidence in flooding along creeks and
streams and areas of poor drainage where deep snow may confine
flow and limit drainage. Significant rises are expected on main
stem rivers. While flooding is not currently forecast, rises to
monitor stage are now forecast for several points, and minor to
moderate flooding can't be ruled out if the system overperforms
in terms of precipitation amounts and/or prolonged periods of
higher snow levels occur.
The flood threat does not go away Sunday. Any additional rains next
week could lead to additional rises, and some rivers will be slow
to respond to the Thursday-Saturday event.
Late Thursday through Saturday, rain combined with strong winds
and high humidity will add considerable energy into our record to
near-record deep regional snowpack at mid to lower elevations.
While higher elevation and deepest snowpacks will continue to
accumulate snow and water equivalent, deep mid-elevation
snowpacks are expected to retain most of the projected rain. Some
of these areas may begin to develop preferential pathways for melt
and start releasing rainfall after prolonged periods of rain, but
are unlikely to contribute significant snowmelt to the runoff. It
is the areas of relatively shallow snowpack on the order of
inches to a couple of feet that we are most concerned about having
significant melt and contributing to the flood concerns.
Fortunately, these areas are confined to low elevation drainages
and to limited portions of the main stem rivers.
Our greatest concern continues to be creeks and streams draining
large areas of terrain with shallow snowpacks (below ~5500 feet)
and urban poor drainage areas where deep snow may be restricting
drainage. Confidence is increasing in flood impacts for these
areas.
The main-stem rivers forecasts have ramped up somewhat, but still
remain below flood stages. Keep a close eye on the Pit River into
Big Valley, the Susan River, The Middle Fork of the Feather, and
the forks and main stem of the Carson River. The Susan River will
respond very rapidly to heavy rain, while the response for the
Pit River into Big Valley and the Middle Fork of the Feather may
take several days. The latest guidance from the CNRFC now has the
East fork of the Carson and the main stem Carson River near
Carson City exceeding monitor stages.
The potential for additional rainfall early next week will require
close monitoring as the Thursday - Saturday system will help prime
the snowpack and stream responses. Check back for forecast
updates at cnrfc.noaa.gov. Changes in storm track could lead to
changes in precipitation and or rain snow elevation that could
exacerbate or mitigate flooding concerns. -Bardsley
&&
.REV Watches/Warnings/Advisories...
NV...High Wind Watch from Thursday evening through Friday evening
NVZ001-003>005.
Flood Watch from Thursday afternoon through Sunday morning
NVZ001>003.
Winter Storm Warning from 4 PM PST Thursday to 11 AM PDT Sunday
NVZ002.
Lake Wind Advisory until 6 PM PST this evening NVZ004.
CA...High Wind Watch from Thursday evening through Friday evening
CAZ070.
Flood Watch from Thursday afternoon through Sunday morning
CAZ071>073.
Winter Storm Warning from 4 PM PST Thursday to 11 AM PDT Sunday
CAZ071.
Winter Storm Warning from 4 PM PST Thursday to 11 AM PDT Sunday
CAZ072.
Winter Storm Warning from 4 PM PST Thursday to 11 AM PDT Sunday
CAZ073.
&&Event by event
6 heavy rain, 4 flood, 4 debris flow, 3 high wind, 2 heavy snow, 1 avalanche. Local standard time, as filed.
Flood, Lyon
- When
- March 9, 3:00 AM PST to March 10, 3:00 AM PST
- Where
- Lyon County, Wellington to 4 mi WNW of Smith
- Cause
- Heavy Rain
- Reported by
- Public
- Coordinates
- 38.750, -119.380
The public reported 4.0 mi SE of Wellington, NV, that Smith Valley fields are ponding and backing up into culverts causing additional problems near desert creek at SR-338.
Heavy Rain, Douglas
- When
- March 9, 6:00 AM PST to March 10, 6:00 AM PST
- Where
- Douglas County, 3.9 mi S of Gardnerville to Minden
- Reported by
- CoCoRaHS
- Coordinates
- 38.874, -119.730
A COCORAHS (NV-DG-11 Gardnerville) located 3.9 mi S of Gardnerville, NV, and a CO-OP Observer (MINN2) located in Minden, NV, reported 24-hour rainfall totals of 1.78 and 1.52 inches respectively.
Heavy Rain, Carson City (C)
- When
- March 9, 6:00 AM PST to March 10, 6:00 AM PST
- Where
- Carson City (C) County, 3.6 mi NNW of Carson City to 3.26 mi WNW of Carson City Arpt
- Reported by
- CoCoRaHS
- Coordinates
- 39.218, -119.806
A COCORAHS, NV-CC-20 Carson City, located 3.6 mi NNW of Carson City, NV, reported a 24-hour rainfall total of 1.62 inches.
Heavy Rain, Douglas
- When
- March 9, 7:00 AM PST to March 10, 7:00 AM PST
- Where
- Douglas County, 5.7 mi W of Gardnerville to 0.24 mi NNE of Mottsville
- Reported by
- CoCoRaHS
- Coordinates
- 38.930, -119.836
A COCORAHS (NV-DG-23 Gardnerville) located 5.7 mi W of Gardnerville, NV, reported a 24-hour rainfall total of 2.27 inches.
Flood, Washoe
- When
- March 9, 7:00 AM PST to March 10, 7:00 AM PST
- Where
- Washoe County, 2.04 mi NNE of Steamboat to 2.03 mi NNE of Steamboat
- Cause
- Heavy Rain
- Reported by
- Public
- Coordinates
- 39.398, -119.736
The public reported 7.0 mi NE of Washoe City, NV, that Toll Road is flooded at Geiger Grade road.
Heavy Rain, Washoe
- When
- March 9, 8:00 AM PST to March 10, 8:00 AM PST
- Where
- Washoe County, 9 mi W of Reno to 22.1 mi NNW of (Rno)cannon Arpt Ren
- Reported by
- CoCoRaHS
- Coordinates
- 39.520, -119.989
A COCORAHS, NV-WH-164, located 22.1 mi NNW of Reno, NV, and COCORAHS, NV-WH-19 Verdi, located 9.0 mi W of Reno, NV, reported 24-hour rainfall totals of 1.7 inches and 1.8 inches respectively.
Heavy Rain, Lyon
- When
- March 9, 8:00 AM PST to March 10, 8:00 AM PST
- Where
- Lyon County, 2.4 mi S of Smith to 0.8 mi NE of Yerington
- Reported by
- COOP Observer
- Coordinates
- 38.765, -119.320
A CO-OP observer (YRGN2) located 0.8 mi NE of Yerington, NV, and mesonet station (NSMV) located 2.4 mi S of Smith Valley, NV, reported 24-hour rainfall totals of 1.50 inches and 1.44 inches respectively.
Heavy Rain, Washoe
- When
- March 9, 9:00 AM PST to March 10, 9:00 AM PST
- Where
- Washoe County, 0.9 mi ESE of Incline Vlg to 1.04 mi E of Incline Vlg
- Reported by
- CoCoRaHS
- Coordinates
- 39.225, -119.934
A COCORAHS, NV-WH-12, located 0.9 mi ESE of Incline Village, NV, reported a 24-hour rainfall total of 2.18 inches.
Avalanche, Greater Lake Tahoe Area
- When
- March 9, 9:15 AM PST to March 10, 9:15 AM PST
- Where
- Greater Lake Tahoe Area forecast zone
- Reported by
- Public
- Coordinates
- 39.789, -119.640 (the zone’s center; the record gives no point)
The public reported 1.0 mi NNW of Diamond Peak Ski Resort that NV-431, the main mountain highway between Reno and Lake Tahoe basin, had been buried by an avalanche. The roadway was covered by some 20 ft. of snow according to the report.
Debris Flow, Lyon
- When
- March 9, 9:42 AM PST to March 10, 9:42 AM PST
- Where
- Lyon County, 24.16 mi SSE of Wellington to 25.47 mi SSE of Wellington
- Cause
- Heavy Rain / Snow Melt
- Reported by
- Public
- Coordinates
- 38.447, -119.156
The public reported 7.0 mi SSE of Sweetwater Summit (Walker River Canyon) of minor debris flows and rock slides. The route was closed from Bridgeport, CA, to Mason, NV, due to flooding along NV-338 on Nevada side.
Debris Flow, Douglas
- When
- March 9, 9:45 AM PST to March 10, 9:45 AM PST
- Where
- Douglas County, 7.53 mi NNW of Topaz Lake to 9.01 mi N of Topaz Lake
- Cause
- Heavy Rain / Snow Melt
- Reported by
- Department of Highways
- Coordinates
- 38.727, -119.558
NDOT reported 3.0 mi NNW of Holbrook Junction that US-395 was closed from Holbrook Jct. to Leviathan Mine Road due to mud and water flows on road.
Flood, Storey
- When
- March 9, 10:00 AM PST to March 10, 10:00 AM PST
- Where
- Storey County, 5.25 mi ESE of Virginia City to 5.25 mi E of Virginia City
- Cause
- Heavy Rain
- Reported by
- County Official
- Coordinates
- 39.304, -119.554
County official reported 2.0 mi WNW Six Mile Canyon that Six Mile Canyon Road was closed from R street in Virginia City, NV, to Sam Clemens St. in Dayton, NV, due to washouts and to allow crews time for road repairs.
Flood, Washoe
- When
- March 9, 10:00 AM PST to March 10, 10:00 AM PST
- Where
- Washoe County, 2.14 mi WSW of Steamboat to 2.74 mi SW of Steamboat
- Cause
- Heavy Rain
- Reported by
- Broadcast Media
- Coordinates
- 39.355, -119.785
The broadcast media reported that 3.0 mi NE of Washoe City, NV, of flooding in Pleasant Valley, NV.
Debris Flow, Mineral
- When
- March 9, 10:38 AM PST to March 10, 10:38 AM PST
- Where
- Mineral County, 11.99 mi WNW of Thorne to 12.14 mi NW of Hawthorne Arpt
- Cause
- Heavy Rain
- Reported by
- Department of Highways
- Coordinates
- 38.689, -118.771
NDOT reported that 2.0 mi NW of Walker Lake, NV, US 95 was closed between Schurz, NV, and Hawthorne, NV, due to a major rockfall.
Debris Flow, Lyon
- When
- March 9, 5:50 PM PST to March 10, 5:50 PM PST
- Where
- Lyon County, 3.7 mi E of Wilson Canyon to 3.52 mi E of Wilson Canyon
- Cause
- Heavy Rain
- Reported by
- Department of Highways
- Coordinates
- 38.821, -119.202
NDOT reported on social media 8.0 mi ENE of Smith, NV, that SR-208 in Wilson canyon was closed due a rockslide.
High Wind, Western Nevada Basin and Range
- When
- March 10, 3:47 AM PST
- Where
- Western Nevada Basin and Range forecast zone
- Measured
- 56 kt (64 mph) measured gust
- Reported by
- Mesonet
- Coordinates
- 39.927, -118.898 (the zone’s center; the record gives no point)
Mesonet station Cherry Valley (CYVNV) located 7.0 mi E of Dixie Valley, NV, reported a peak wind gust of 65 mph.
High Wind, Greater Reno/Carson City/Minden Area
- When
- March 10, 5:30 AM PST to 8:00 AM PST
- Where
- Greater Reno/Carson City/Minden Area forecast zone
- Measured
- 71 kt (82 mph) measured gust
- Reported by
- Mesonet
- Coordinates
- 39.511, -119.499 (the zone’s center; the record gives no point)
Mesonet station (SLIDE) located 0.9 mi ESE of the Mount Rose Summit (DRI), mesonet station South Verdi (NV052) located 2.0 mi SSE of Verdi, NV, and mesonet station (WASNV) located 1.3 mi SW of Washoe City, NV, reported maximum wind gusts of 82 mph, 76 mph, and 73 mph respectively.
Heavy Snow, Greater Lake Tahoe Area
- When
- March 10, 7:00 AM PST to March 11, 7:00 AM PST
- Where
- Greater Lake Tahoe Area forecast zone
- Reported by
- Public
- Coordinates
- 39.789, -119.640 (the zone’s center; the record gives no point)
The public located 1.0 mi NE of the Diamond Peak Ski Base reported a 24-hour snowfall total of 10.0 inches with a 2-day snowfall total of 14 inches at 8500 feet.
High Wind, Western Nevada Basin and Range
- When
- March 10, 9:00 AM PST to 11:00 AM PST
- Where
- Western Nevada Basin and Range forecast zone
- Measured
- 53 kt (61 mph) measured gust
- Reported by
- Mesonet
- Coordinates
- 39.927, -118.898 (the zone’s center; the record gives no point)
Mesonet station Mill City (UP983) located 1.4 mi W of Mill City, mesonet station Toulon (TOUNV) located 10.1 mi of Trinity Junction, NV, and mesonet station (UP974) located 17.5 mi NE of Gerlach, NV, reported peak wind gusts 59 mph, 60 mph, and 61 mph respectfully.
Heavy Snow, Greater Lake Tahoe Area
- When
- March 11, 7:00 AM PST to March 12, 7:00 AM PST
- Where
- Greater Lake Tahoe Area forecast zone
- Reported by
- Public
- Coordinates
- 39.789, -119.640 (the zone’s center; the record gives no point)
The public located at the Mount Rose Ski Base reported a 24-hour snowfall total of 12.0 inches with a 3-day storm total snowfall of 36-44 inches.
- Flood
- Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
- Avalanche
- A mass of snow sliding down a mountainside that caused a death, an injury or damage.
- Debris Flow
- A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire.
- High Wind
- Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
- Heavy Snow
- Snowfall reaching the local warning threshold without the other hazards of a winter storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Winter Storm and Winter Weather in Wisconsin, March 9 to 10, 20231 death · $70,000 · 20 events
- Flooding and High Wind in California, March 9 to 14, 20231 death · 2 injured · $90 · 75 kt wind · 14 events
- Flooding and Heavy Snow in Nevada, March 9 to 22, 2023$13 million · 66 kt wind · 37 events
- Avalanche and Flood in California, March 9 to 14, 2023$3.0 million · 3 events
- Flash Flooding and Flooding in California, March 9 to 10, 2023$6,000 · 110 events
- Winter Storm and Avalanche in Idaho, March 9 to 11, 2023$209,000 · 66 kt wind · 31 events
- Flash Flooding and Flooding in Texas, March 9, 2023$215,000 · 1 in hail · 11 events
- Winter Storm and Heavy Snow in Montana, March 9 to 11, 202367 kt wind · 22 events
- Flooding and Heavy Snow in California, March 9 to 12, 202389 kt wind · 18 events
- Winter Weather in Minnesota, March 9 to 10, 202314 events
- Flash Flooding and High Wind in California, March 9 to 10, 202359 kt wind · 13 events
- Heavy Snow and High Wind in California, March 9 to 13, 2023100 kt wind · 9 events
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: 1099342, 1099138, 1099144, 1099140, 1099343, 1099141, 1099145, 1099146, 1099341, 1099344, 1099345, 1099347, 1099350, 1099351, 1099352, 1099134, 1099136, 1099148, 1099133, 1099149.