Heavy snow over the Blue Mountains and Kittitas Valley February 15-17 with 8-11 inches of snow in the mountains and 5-6 inches of snow in the valley.
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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.
Heavy snow over the Blue Mountains and Kittitas Valley February 15-17 with 8-11 inches of snow in the mountains and 5-6 inches of snow in the valley.
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 Feb 15, 3:25 AM PST, 35 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
325 AM PST Sat Feb 15 2020
Updated Aviation Discussion
.SHORT TERM...Today through Monday night...Overall pattern has an
upper level trough over the central United States and an upper level
ridge in the eastern Pacific Ocean. This is placing the Pacific
Northwest under a west to northwest flow with a moisture plume set
to come over the ridge and into the region today and overnight. This
pattern will favor the Cascades and eastern mountains with snow
while elevations around 3000 feet and below see just rain. The
westerly flow will produce a rain shadow along the east slopes of
the Cascades and western Columbia Basin resulting in limited
moisture. The same west flow will produce a favorable upslope flow
into the eastern mountains of Oregon and numerous winter storm
warnings and advisories are in effect. This moisture plume will
impact the forecast area this afternoon and overnight but slowly
sink southward over time to be over southern Oregon by Sunday
afternoon. As this happens the flow will turn more northwesterly
Sunday through Monday ushering in some colder air and lowering snow
levels down to around 1500-2000 feet. Precipitation Sunday night and
Monday will continue to be confined mainly to the Cascade crest and
over the eastern mountains with some further snow accumulations
possible especially in the Blue Mountains. There will be some breezy
to windy conditions today through Sunday and then winds decrease
through the remainder of the short term. Precipitation associated
with this moisture plume will cause small streams and creeks to rise
which in turn will lead to a rise in the main stem rivers over the
weekend. However, at this time there is no expectation that this
event will result in or lead to any flooding as this is a short
duration event, Also, temperatures in the mountains remain cold
preventing any significant snowmelt from occurring.
.LONG TERM...Tuesday through Saturday...The forecast for Tues-Thurs
calls for dry conditions, and all the deterministic models agree
with an upper level ridge and surface high over the Pacific NW. The
axis of the ridge will be offshore Tuesday shifting eastward along
the Cascade Range Wednesday then over ID on Thursday. There will be
three days of dry and stable conditions and a gradual warming trend.
There could be patchy fog and freezing fog at night, but we are
approaching about 10.5 hours of daylight with limited potential for
widespread fog.
Models differ the remainder of the forecast period, and one could
forecast mountain showers (ECMWF) or continued dry conditions (GFS
and GEM) for Thursday night through Friday night. The GFS and GEM
advertise a closed low developing off the CA coast during this time,
leaving WA/OR under a split flow aloft and relatively dry. The ECMWF
maintains a more consolidated flow and a shortwave trough bringing a
chance of snow to the Cascades and a slight chance over the eastern
mountains. Since the GFS and GEM support the ensembles, the EC could
be the outlier. Will keep the NBM PoPs of around 30-40 pct for the
east slopes of the WA and northern OR Cascades, but these may be
lowered or drop if the EC comes into agreement with the other models.
Models are in general agreement with a stronger shortwave trough on
Saturday, increasing the threat of precipitation over the forecast
area Saturday night. Preliminary snow levels are around 4000-4500
feet Saturday and Saturday night. Wister
&&
.AVIATION...12Z TAFs...Aviation conditions will range from VFR at
KDLS, KYKM and KPSC to MVFR at KALW and KPDT to IFR at KRDM and
KBDN. Light snow will develop at KRDM and KBDN in the next several
hours, reducing conditions to IFR...possibly LIFR. Snow will change
to rain in the afternoon at these two sites, and a good chance of
MVFR in showers. Precipitation will fall as rain off and on during
the day at KALW and KPDT with MVFR conditions likely, but there is
even a possibility of IFR CIGS/VSBY in moderate rain. As the frontal
band moves south this evening, conditions will improve to mid level
BKN-OVC. Those stations in VFR will have CIGs around 4K-8K feet AGL.
SW-W winds of 8-15 kts with local gusts around 25 kts can be
expected. Wister
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 47 36 47 32 / 70 80 20 20
ALW 48 36 48 33 / 70 90 20 40
PSC 51 35 52 32 / 50 50 0 10
YKM 50 30 51 29 / 20 10 10 10
HRI 51 36 51 34 / 50 70 10 10
ELN 45 29 44 28 / 20 10 10 10
RDM 48 33 47 26 / 40 50 20 20
LGD 41 32 41 27 / 80 100 30 40
GCD 42 35 42 26 / 80 90 60 30
DLS 46 36 47 34 / 60 60 10 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 AM PST Sunday for ORZ050-503-
506.
Winter Storm Warning until 10 AM PST Sunday for ORZ502.
WA...Winter Storm Warning until 10 AM PST Sunday for WAZ030.
&&
91/85/85The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
Eleven inches of snow at Ski Bluewood, 8 inches at Touchet Snotel.
New snow of 5-6 inches across the valley.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2020Every state in 2020This day in weather historyWarnings in Washington, February 2020
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: 870209, 870208.