A robust warm-frontal boundary facilitated a period of strong downslope across the Blue Mountain foothills the evening of December 9th through the morning of December 10th.
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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 PDT wrote it up.
A robust warm-frontal boundary facilitated a period of strong downslope across the Blue Mountain foothills the evening of December 9th through the morning of December 10th.
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 Pendleton, OR wrote its last area forecast discussion before the first event at Dec 9, 2:55 PM PST, 5 hours 5 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
255 PM PST Fri Dec 9 2022
.SHORT TERM...Friday through Sunday...A complex weather set-up is in
store for the region this evening as a potent upper-level trough
looks to deepen as it makes its way toward the western CONUS. May
areas will see disparate impacts due to differences in temperature,
precipitation types, and amounts, so will go through each region to
discuss potential impacts with this system, focusing primarily on a
period extending from this evening until Saturday night.
Cascades...Current radar imagery showing precip beginning to bear
down on the Cascade crests, expected to begin within the next couple
of hours. The bulk of the snowfall associated with this event will
occur between a window of 4PM and 10PM, with lighter showers
lingering into the day Saturday. Warnings are in effect all along
our Cascade zones, with highest impacts expected above 4000 ft for
the WA Cascades, and above 4500 ft for the Oregon Cascades. Due to
the strength of the moisture transport oriented more meridional
than is typical of winter storms in our area, not expecting heavy
snow along the east slopes of the OR Cascades (namely La Pine and
Sunriver) with some shadowing evident across guidance for Snoqualmie
Pass as well. Still expecting snow of a couple of inches for these
areas, but the bullseye for snowfall looks to fall more towards the
WA Cascades in Yakima and Klickitat County.
Yakima/Kittitas Valleys...Winter storm warning remains in effect for
the Kittitas Valley, with an advisory in the Yakima Valley. Guidance
did come down on QPF just slightly for these two areas, but still
confidence in an impactful snow event through Saturday morning.
Given the freezing fog and low stratus that has lingered around for
much of the day today, expecting warmer air to have a much more
difficult time mixing down into these areas. As a result, have
scaled back on wording with regards to freezing rain potential,
expecting a primarily snow event, but that being said, areas along
the east slopes of the Cascades should still be wary of potential
patchy freezing rain once the warmer air begins to surge in aloft
during the overnight hours. Bulk of precip should start to taper
down by sunrise.
Lower Basin/Columbia River Gorge...Forecast confidence admittedly a
bit shaky for these areas, as lower stratus and fog have insulated
the area today and have allowed the cold pool to strengthen a bit.
Models are still aggressive on bringing in icy precip to the lower
Basin this evening, but opted to go for colder snow levels in the
forecast, in light of last night's system and current temperatures.
Still, model QPFs aren't too high for the lower Basin and the Gorge
remains relatively warm this afternoon, so will mostly be
advertising a light snow transitioning to rain for the area
overnight, with some patchy freezing rain possible for the Tri-
Cities and Hermiston.
Foothills of the Blues/Grande Ronde Valley...Impacts here are
expected to be primarily wind-based, as the synoptic setup for this
event is typical for a strong downsloping wind event. Temperatures
are also up into the low 40s for Pendleton and Walla Walla this
afternoon. La Grande could see some light snow accumulations, as
some cold pooling may linger around for a bit, but am primarily
advertising the Wind Advisories in effect for these areas, as winds
pick up overnight extending into Saturday afternoon. Gusts could
exceed 50 mph in some areas early Saturday morning.
Blue Mountains and John Day/Ochoco Highlands...Winter Weather
Advisories are in effect for these areas, namely for elevations
above 4000 ft, as moisture transport for these areas isn't as
aggressive as across the Cascades. Started out as a potentially low-
end advisory event, but latest QPF guidance did increase amounts a
bit, mainly for the northern Blues. Expect snow to begin around 9PM,
with light showers lingering through Saturday, primarily in the
eastern mountains.
Elsewhere, precip may start as a light snow before transitioning to
rain, before much of the forecast area clears out by early Saturday
evening. Models have hinted at the potential for a wraparound
moisture event on Sunday that would effect primarily central OR up
through the John Day/Ochoco Highlands, so will have to keep an eye
on how guidance evolves as soon as this evening's weather system
swings through our area. Evans/74
.LONG TERM...Monday through Friday...Confidence in the upper-level
pattern is generally very high through Monday night with the current
cool, wet pattern this weekend transitioning to a cold, drier
pattern as a cut-off low continues to dig south and east into the
Great Basin and ushers in colder air in its wake as flow aloft over
the Pacific Northwest turns northerly and then easterly. However,
Tuesday onward, ensemble and deterministic guidance begin to diverge
with regard to the details of the pattern, mainly the longitudinal
placement of an incoming cut-off low in the northeast Pacific
(somewhere between 40-60% of ensemble member variance per 12Z
cluster analysis). Main impacts with this pattern (low pressure
offshore or over western Oregon and high pressure inland) would
include cold, below-normal temperatures, low stratus and fog for
basin and valley locations, and slight chance of light freezing
drizzle/flurries. The ECMWF EFI only highlights the potential for
atypically cold temperatures relative to model climatology, with EFI
values somewhere between -0.6 and -0.8 for eastern Oregon and
eastern Washington for Monday onward. Plunkett/86
&&
.AVIATION...00Z TAFs...A winter weather system is forecast to bring
another round of impacts to all TAF sites through the next 24 hours.
Onset of precipitation for DLS/BDN/RDM/YKM is expected this
afternoon after 00Z with precipitation spreading east to PSC/PDT/ALW
by 04-05Z. -FZRA is a concern for PSC through the TAF period due to
lingering cold air trapped in the Columbia Basin, especially since
morning FZFG failed to fully lift this afternoon. Elsewhere,
forecast soundings would indicate precipitation at YKM should remain
SN through the event with a mix of -RA and -SN for other sites.
Other concerns are downslope winds for ALW where 12Z HREF guidance
suggests 70-100% probability of exceeding 40 kt gusts 05Z Saturday
to 21Z Saturday and 20-40% chance of exceeding 50 kts. PDT has a
more modest 40-80% chance of exceeding 30 kt gusts during the same
period. Model uncertainty for strong wind gusts at BDN/RDM is
significantly higher than for PDT/ALW (run-to-run and model-to-
model), as guidance continues to struggle resolving how much these
winds will come off the Cascades and mix down into the lower
elevations of central Oregon. Plunkett/86
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 33 44 28 36 / 70 40 30 40
ALW 33 45 30 38 / 80 60 20 40
PSC 29 40 30 37 / 80 50 20 40
YKM 25 37 26 39 / 100 60 20 30
HRI 32 43 29 37 / 70 30 30 40
ELN 23 36 26 39 / 100 60 10 20
RDM 33 45 24 36 / 80 30 40 30
LGD 28 39 29 38 / 80 60 30 40
GCD 29 42 27 37 / 90 60 40 40
DLS 34 43 34 42 / 100 60 40 40
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 7 PM this evening to 4 PM PST Saturday for
ORZ049-507-508.
Winter Weather Advisory from 8 PM this evening to 7 PM PST
Saturday for ORZ502-503-506.
Winter Storm Warning until 7 PM PST Saturday for ORZ509.
WA...Wind Advisory from 7 PM this evening to 4 PM PST Saturday for
WAZ029.
Winter Weather Advisory from 8 PM this evening to 7 PM PST
Saturday for WAZ030.
Winter Storm Warning until 7 PM PST Saturday for WAZ520.
Freezing Fog Advisory until 4 PM PST this afternoon for WAZ026-
028.
Winter Storm Warning until 4 PM PST Saturday for WAZ026-521.
Winter Weather Advisory until 4 PM PST Saturday for WAZ027.
&&
SHORT TERM...74
LONG TERM....86
AVIATION...86PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
217 PM PST FRI DEC 9 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 PM HEAVY SNOW 1 W WHITE SALMON 45.73N 121.51W
12/08/2022 E4.0 INCH KLICKITAT WA TRAINED SPOTTER
STORM TOTAL AND TIME ESTIMATED.
&&
ETPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
244 PM PST FRI DEC 9 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 PM SNOW 5 SE WHITE SALMON 45.68N 121.40W
12/08/2022 E1.0 INCH WASCO OR TRAINED SPOTTER
1 INCH OF SNOW IN 12 HOURS.
&&
JASThe national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The Mesonet station AS881 measured a gust of 77mph at 0130 on December 10th and the Mesonet station E8735 measured a gust of 59mph at 0000 on December 10th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2022Every state in 2022This day in weather historyWarnings in Oregon, 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 2026-09-24. Each event’s entry at NCEI: 1069661.