An atmospheric river associated with a midlatitude cyclone brought greater than 2 inches of rainfall to the Sierra Nevada and 1 to 2 feet of snowfall above 7000 feet in the Lake Tahoe Basin and in Mono County. 50 inches.
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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 REV wrote it up.
An atmospheric river associated with a midlatitude cyclone brought greater than 2 inches of rainfall to the Sierra Nevada and 1 to 2 feet of snowfall above 7000 feet in the Lake Tahoe Basin and in Mono County. Rainfall totals in northeast California and the lower valleys of northern Mono County ranged from around 0.50 inches up to nearly 1.50 inches. Freezing levels derived from WFO Reno soundings rose slowly throughout the event.
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 Nov 30, 3:01 PM PST, 8 hours 59 minutes earlier.
Area Forecast Discussion
National Weather Service Reno NV
301 PM PST Sat Nov 30 2019
.SYNOPSIS...
Snow showers in the Sierra intensify this evening and overnight,
with moderate to heavy snow continuing into Monday. This storm
will also produce a mix of snow, rain, and possibly ice for Sierra
valleys and out across western Nevada. After a breather Tuesday,
more precipitation is on the way for the middle of next week and
next weekend.
&&
.SHORT TERM...
Main change to bump snow levels a bit higher (to near the mid-
range of snow level guidance) Sunday afternoon through Monday,
mainly for valleys in northeast CA and western NV. This did not
change snowfall potential much and the slight chance for freezing
rain remains for lower valleys.
* The bottom line remains unchanged: A chaotic forecast in terms
of winter precipitation and large valley-by-valley differences
in precipitation character can be expected Sunday and possibly
into early Monday. Expect difficult travel conditions and long
waits in the Sierra, especially above about 6500 feet (7000 feet
Mono County). Possible difficulties remain in western Nevada,
most likely late tonight and Sunday morning, with areas farther
north and northeast possibly having light ice issues longer.
Blended model guidance (NBM) is showing a much better chance for
snow to change over to rain by late morning and afternoon in
western Nevada valleys and for the Lake Tahoe Basin. Also,
contingency snow level grids have warmed some. With these factors
and the fact that the NBM has been trending this way recently,
have bumped up snow levels some Sunday and Monday. That being
said, the lower-end chance for freezing rain still cannot be
discounted Sunday and Sunday night for valleys across the western
Great Basin, including the Carson Valley (into early afternoon
Sunday), Honey Lake Basin, and perhaps the Carson Sink. A note
about freezing rain: it can be self-limiting. If there is no cold,
drier air to be brought in when rain freezes to surfaces, the
freezing process actually adds heat to the air! Therefore, if any
freezing rain or drizzle develops in the Carson Valley or other
locations in far western NV, I would expect it to be fairly
limited in time (perhaps a few hours).
Turning to snowfall potential, there has not been much change
with 1.5 to 4 feet of mostly "cement" in the high Sierra, 4 to 10
inches in the Tahoe Basin and far northeast CA (higher amounts
west/southwest of Susanville above 5500 feet), and a few inches
for other valleys across far western Nevada and in Mono County.
Still, subtle changes in precipitation rates, depth of warm layers,
and temperatures will have large implications on phase
characteristics for each valley and some impact on snow totals. It
is quite possible that precipitation will change from snow to rain,
back to snow, to a mix, and back again (with a little freezing
precipitation) through Sunday morning before warming aloft is
sufficient to allow for more stable rain in valley locations. One
thing that can be said; when snowing, the character of the snow
will be very wet and should limit accumulations while allowing for
lousy traction where it does accumulate.
Conditions begin to improve slowly Monday and more rapidly Monday
night as the upper low in the eastern Pacific digs south and the
associated moisture tap/AR weakens. Expect precipitation to taper
down Monday with the main snowfall accumulation expected through
Sunday night. -Snyder
.LONG TERM...Tuesday through Saturday...
Light upslope driven snow showers will linger across the Sierra on
Tuesday morning followed by a brief break Tuesday afternoon. A weak
area of low pressure off the coast will provide another chance of
snow showers Wednesday morning/afternoon with the best potential
roughly south of Highway 50. Did trend chances a bit higher in the
forecast with slightly higher snowfall amounts. Overall Mono and
Mineral counties looks to see best chances of picking up an
additional 1-5" of snowfall.
A stronger winter storm continues to show the potential to provide
another round of heavy mountain snow with valley rainfall next
weekend. After a relatively quiet period in the weather on Thursday,
a swath of moisture begins to push across the Sierra most likely in
the late Friday timeframe. Have continued to favor the slower onset
timing for Friday evening shown by the EC ensemble and majority
cluster analysis. This looks to be a fairly progressive (quick
moving) storm which may limit precipitation totals somewhat.
However, with a subtropical moisture tap there could be about a 12
hour period next Friday into Saturday with very high precipitation
rates in the Sierra and another round of significant travel impacts.
Fuentes
&&
.AVIATION...
Significant winter storm to impact the Sierra and western Nevada
terminals this evening through Monday.
WIND:
* Strong and gusty winds are expected to be confined to high
elevations with much lighter gusts (<25kts) at valley terminals
through the storm.
* The approaching storm will increase winds this evening with
gusts across the ridgetops near 80-100 mph possible by 03z this
evening and lasting through Monday morning.
* A prolonged period of moderate-severe turbulence is possible
along and east of the Sierra through at least Monday morning.
SNOW/RAIN/FREEZING RAIN POTENTIAL:
* This storm will start as all snow tonight for the terminals but
will transition to a rain/snow mix through Sunday as rising snow
levels are expected. A brief period of FZRA is also possible.
Mountain obscuration from cloud cover is ongoing and will
continue through Monday.
* Tahoe Terminals: For KTRK/KTVL, light snow showers possible
after 03-04z this evening, with heavier snow arriving after
about 08z. IFR conditions expected during mod-heavy snow.
Heavy, wet snow accumulations of 3-6" possible by Sunday
morning. Snow changing to rain possible between 15-18z(low-mod
confidence on timing). Brief period of FZRA during changeover
increasing the likelihood of low level clear icing with chances
generally below 10%.
* Western NV Terminals: For KRNO/KCXP/KMEV, snow onset expected
after 07-08z this evening, with 1-3" of heavy, wet snow possible
by Sunday morning. IFR conditions expected during mod-heavy
snow. Snow change over to rain possible between 15-18z(low-mod
confidence w/ timing). Brief period of FZRA during changeover
increasing the likelihood of low level clear icing with chances
generally below 10% KRNO and 25% for KMEV.
* Mammoth: Snowfall onset expected after 08-09z with 2-5 inches of
accumulation possible through Sunday afternoon. A rain-snow mix
possible by Sunday evening.
The storm continues through Sunday and Monday before winding down
late Monday night.
&&
.REV Watches/Warnings/Advisories...
NV...Winter Storm Warning from 4 PM this afternoon to 10 AM PST
Monday NVZ002.
Winter Weather Advisory from 7 PM this evening to 4 PM PST
Sunday NVZ003.
CA...Winter Storm Warning from 4 PM this afternoon to 10 AM PST
Monday CAZ071.
Winter Storm Warning from 7 PM this evening to 10 AM PST Monday
above 7000 feet in CAZ073.
Winter Storm Warning from 4 PM this afternoon to 10 AM PST
Monday CAZ072.
&&
For more information from the National Weather Service visit...
http://weather.gov/renoThe national radar mosaic for the moment the first event began.
13 heavy rain, 6 heavy snow, 1 debris flow. Local standard time, as filed.
HADS station ERYC1 at Ellery Lake reported 1.70 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 9504 ft MSL.
SNOTEL station LELC1 at Leavitt Lake reported 4.50 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 9602 ft MSL.
SNOTEL EBTC1 at Ebbetts Pass reported 6.60 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 8660 ft MSL.
SNOTEL BSKC1 at Burnside Lake reported 4.40 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 8158 ft MSL.
RAWS MKEC1 near Markleeville reported 1.98 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 5501 ft MSL.
SNOTEL ECOC1 at Echo Peak reported 4.90 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 7652 ft MSL.
ASOS KTVL at South Lake Tahoe Airport reported 1.88 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 6257 ft MSL.
SNOTEL FLFC1 at Fallen Leaf Lake reported 3.30 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 6241 ft MSL.
SNOTEL near the headwaters of Ward Creek reported 4.90 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 6764 ft MSL.
SNOTEL near Independence Lake reported 4.50 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 8337 ft MSL.
Denten Creek RAWS MWKC1 near Blairsden reported 2.84 inches of rainfall in a 48-hour period from 1 December 0000PST to 2 December 2359PST. Station elevation of 5149 ft MSL.
Mammoth Mountain Ski Area reported 31 inches of snowfall in a 2-day period from the 30th of November through the morning of December 2nd at their mid-mountain location of 9014 feet MSL.
Heavenly Ski Resort reported 18 inches of snowfall in a 2-day period from the 30th of November through the morning of December 2nd at an elevation of 6540 feet MSL.
Squaw Valley Ski Resort reported 37 inches of snowfall in a 2-day period from the 30th of November through the morning of December 2nd at their mid-mountain location of 8200 feet MSL.
Alpine Meadows Ski Resort reported 31 inches of snowfall in a 2-day period from the 30th of November through the morning of December 2nd at their upper-mountain location of 8000 feet MSL.
Northstar Ski Resort reported 37 inches of snowfall in a 2-day period from the 30th of November through the morning of December 2nd at their mid-mountain location of 6900 feet MSL.
CO-OP observer at Tahoe City reported 3.07 inches of rainfall in a 48-hour period from 1 December 0700PST to 3 December 0700PST. Station elevation of 6230 ft MSL.
CO-OP observer at Sierraville reported 2.13 inches of rainfall in a 48-hour period from 1 December 0700PST to 2 December 0700PST. Station elevation of 4975 ft MSL.
June Mountain Ski Area reported 12 inches of snowfall in a 1-day period from the morning of the 1st through the 2nd at an elevation of 7545 feet MSL.
A rockslide occurred within the westbound lane of US Highway 50 approximately 2 miles east of Echo Summit on 2 December 1315PST. The highway was closed for approximately one hour to clean up. One lane controls lasted for approximately 5 to 6 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, December 2019
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: 868871, 868877, 868879, 868880, 868886, 868898, 868899, 868900, 869114, 869115, 869119, 869135, 869136, 869149, 869150, 869151, 868901, 869116, 869147, 877248.