An upper-level trough swept through the forecast area starting the overnight period of the 15th/16th into the early morning hours of the 17th, bringing heavy snowfall to the mountains of central Oregon.
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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.
An upper-level trough swept through the forecast area starting the overnight period of the 15th/16th into the early morning hours of the 17th, bringing heavy snowfall to the mountains of central Oregon.
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 15, 9:54 AM PST, 4 hours 6 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
954 AM PST Sun Dec 15 2024
.UPDATED AVIATION DISCUSSION...
.AVIATION...18Z TAFs...While all sites are currently in VFR, flight
categories will then deteriorate to MVFR or less starting tonight
through tomorrow morning. The next frontal system arriving will
bring precip to KYKM, KRDM and KBDN with low CIGs and VSBYs with
rain/snow mix and possibly fog. Mainly rain will occur for KDLS,
KPDT, KALW, and KPSC through tomorrow morning. Winds will be less
than 12 kts for most sites except KPSC with gusts at 24 kts.
Feaster/97
&&
.SHORT TERM...Today through Tuesday...The short term will be very
active as we see precipitation coming to a brief respite later
today across our mountain zones, but by late this evening the next
impactful system will begin another round of mountain snow worthy
of highlights for our region.
Mountain snow continues to move over the Cascades as of this
morning, with an advisory remaining in effect for the Oregon side.
Much of this activity is subsiding just after the peaks and
crests, but several more inches of snow is expected through the
morning hours. Meanwhile, meaningful snow has essentially
dissipated across the Blue Mountains this morning. A few more
inches may be possible through the day for the highest peaks of
the area as some scattered snow showers may redevelop during the
morning hours, but by the early afternoon expect this to be
essentially gone. Because of this, have cancelled the remainder of
the winter weather advisory for the Blues in lieu of a new
advisory for the next system moving into the region.
A Pacific low will swing a warm front into the region later
tonight with the remainder of this system including a weakening
cold front then moving inland through Tuesday. Snow levels begin
around 1.5-3k feet, and will steadily increase through Tuesday.
This will allow the bulk of our meaningful snowfall to occur
between 3.5-4k feet during this next event. The NBM paints several
areas of 48-hour snowfall 10+ inches for our mountain zones at
50-90%, highlighting the Oregon Cascades in particular. In fact,
our Oregon zones should see a much longer duration event than our
Washington zones thanks to a second push of QPF overnight Monday
into Tuesday. Because of this, winter weather advisories have
been issued for the WA upper and lower slopes of the Cascades as
well as the northern Blue Mountains of OR/WA, along with a Winter
Storm Watch for the OR Cascades/southern Blue Mountains and
Ochoco-John Day Highlands.
Our lower elevation zones will also see precipitation during this
event, but with high temperatures hovering in the 40's and lows in
the mid to low 30's, most QPF will fall as rain, occasionally
mixing with snow. Precipitation will then decline on Tuesday,
though lingering showers/snow showers in the mountains is expected
through the end of the short term into Wednesday morning.
Goatley/87
.LONG TERM...Wednesday through Sunday...No major weather concerns
are anticipated through the end of the week, but Sunday is looking
like the next focus for widespread precipitation and isolated high
winds.
Models have consistently advertised a fast moving shortwave on
Wednesday, flattening the weak transitory ridge and bringing a
period of rain and mountain snow (snow levels around 4500-5500
feet). The chance for precipitation across the Columbia Basin down
the Columbia Deschutes Plateau and east of the Blue Mtns is only a
20-40% chance due to rain shadowing off the Cascades and Blue
Mountains in the strong westerly flow. Despite the high PoPs of 60-
90%, the QPF and snow amounts will be low. Once again, it's a fast
moving system with limited duration of precipitation. It will be
windy along the exposed ridges and breezy in the lower elevations--
windy along I-84 from Ladd Canyon to Cabbage Hill. Overall
confidence in Wednesday's forecast is 80% due to good run-to-run
continuity of the models.
Wednesday night through Friday night is looking like a dry forecast
with the exception of the Cascade east slopes where PoPs are
generally 30-50% over the WA side and 15-30% over the OR side.
Models are in good agreement of an upper level ridge strengthening
over eastern WA/OR late Wednesday night through Friday then shifting
eastward on Friday. Precipitation associated with a warm front over
western WA Thursday afternoon and evening will slop over the eastern
side of the Cascades with light precipitation...mainly north of the
the Columbia Gorge.
Latest runs show the axis of the ridge along the northern Rockies on
Friday with an increasing southerly flow. However, there are slight
differences on the timing as well as the amplitude of the ridge to
the east and amplitude of the trough offshore. These differences
will mainly affect the sensible weather forecast for the west side
of the Cascades, but about 35% of the GEFS and 55% of the Canadian
ensembles (less than 10% of the EC ENS) show limited QPF along the
WA/OR Cascades Friday. Again, PoPs are only 20-40% so not worth
getting excited about. The differences are more pronounced on
Saturday, therefore confidence in precipitation for the CWA is low.
It's basically a 50/50 split of a dry southwest flow or light
precipitation ahead of the offshore trough.
Sunday (Day 8) has a chance for widespread precipitation and hints
of an atmospheric river, although the AR forecasts from the GFS and
ECMWF do not go out that far just yet. This is based on the
deterministic and ensembles upper level synoptic pattern with a
moist southwest flow tapping in subtropical moisture on some, but .
not all, of the runs. I don't have high confidence at this time,
but it is worth mentioning. Wister/85
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 45 31 40 32 / 10 50 100 60
ALW 46 34 41 33 / 30 30 100 60
PSC 47 34 39 34 / 10 30 100 50
YKM 40 29 37 27 / 0 70 90 50
HRI 47 34 40 33 / 10 50 90 50
ELN 40 28 37 27 / 0 70 90 40
RDM 40 31 42 31 / 20 80 60 70
LGD 40 29 38 30 / 50 50 100 70
GCD 39 28 41 32 / 20 80 100 70
DLS 42 36 41 37 / 20 100 100 80
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory from 10 PM this evening to 10 PM PST
Monday for ORZ502.
Winter Storm Watch from this evening through Tuesday morning for
ORZ503-506-509.
Winter Weather Advisory until 10 AM PST this morning for ORZ509.
WA...Winter Weather Advisory from 10 PM this evening to 10 PM PST
Monday for WAZ030.
Winter Weather Advisory from 10 PM this evening to 4 PM PST
Monday for WAZ522-523.
&&
SHORT TERM...87
LONG TERM....85
AVIATION...97The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
SNOTEL sites Ochoco Meadows and Lake Creek reported 8 and 5 inches of snow, respectively, between late Sunday the 15th and the morning of Tuesday the 17th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2024Every state in 2024This day in weather historyWarnings in Oregon, December 2024
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: 1226045.