A persistent ridge sat over the area for several days, with strong high pressure solidly entrenched over the Columbia River Basin, and relatively lower pressure west of the Cascade Crest. With a strong pressure gradient across the Cascades, the Columbia River Gorge developed very strong winds which persisted for several days.
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 PQR wrote it up.
A persistent ridge sat over the area for several days, with strong high pressure solidly entrenched over the Columbia River Basin, and relatively lower pressure west of the Cascade Crest. With a strong pressure gradient across the Cascades, the Columbia River Gorge developed very strong winds which persisted for several days.
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 Portland, OR wrote its last area forecast discussion before the first event at Dec 6, 11:10 PM PST, 3 hours 9 minutes earlier.
Area Forecast Discussion...Updated Aviation/Marine Section
National Weather Service Portland OR
1109 PM PST Wed Dec 6 2017
.SYNOPSIS...Dry and locally windy weather will persist through the
upcoming weekend as strong high pressure dominates our weather.
&&
.SHORT TERM...Tonight through Saturday...The pressure gradient across
the Columbia River Gorge is nudging up again this evening to -9.9mb
TTD-DLS. Tonight and Thu morning looks to be another windy period in
the western Gorge, then pressure gradients begin to relax and winds
will follow suit. The windiest observed location, Crown Point gusted
to 69 mph at 6 pm this evening, while right along the river at
Rooster Rock gusted to 49 mph 11 am today. Expected peak gusts
tonight and Thu should be close to those numbers. Got only one
damage report today - in Cascade Locks 1 inch diameter by 4-5 ft
pine tree branches were breaking off. East Portland/Vancouver
metro area also quite windy with peak gusts today in the 40 to
50 mph range.
Aside from the strong east winds in and near the Columbia Gorge, the
main forecast issue the next few days will be fog and subfreezing
temperatures. Forecast did not turn out very well especially for
portions of the central and south Willamette Valley where the
north-to-south pressure gradient was stronger than expected. This
resulted in more wind at the surface leading to high temps well into
the 50s. Winds should be weaker Thu in that area, but still enough
to break the inversion. So have increased high temps especially along
the west side of the valley where winds should keep the temps up.
The lower Columbia and Eugene area likely to see the most fog tonight
and Thu am with freezing fog likely. Could see a couple of slick
spots on roads, but wouldn't expect much with good heating today
likely helping to keep road surface temperatures well above freezing.
Temperature forecasting will be tricky the next several days, as much
will depend on inversions due to the unseasonably warm air mass
aloft. Exposed slopes, ridges, and coastal areas will be several
degrees above normal, possibly nearing record territory as 850 mb
temps warm to as much as +16 deg C. Meanwhile, areas stuck under
inversion will likely be below normal with temps struggling to get
out of the 30s during the day and subfreezing nights. Although we
haven't seen this scenario yet this week, it should become more
likely as the top of the inversion lowers and winds subside Thu
night.
Near the Gorge, daytime temps will be fairly seasonable in the 40s,
but the wind will make it feel much colder. The area stuck under
inversion and cooler/more stagnant air will likely grow over the next
2-3 days as winds aloft decrease. As usual in these situations, the
central and south Willamette Valley will tend to have the worst
stagnation, and the Air Stagnation Advisory still looks valid for
these areas especially Thu night into the weekend. /mh
.LONG TERM...Saturday night through Wednesday...The extended period
will literally just be an extension of the short term with continued
dry weather as an upper level ridge of high pressure remains over the
Pacific NW. The surface high looks to remain east of the Cascades
which will keep the flow offshore. A strong low level subsidence
inversion will allow areas of fog and low clouds to persist in
wind-sheltered inland valleys. Additionally, temperatures will remain
cool in the inland valleys, with warmer temperatures near the coast
and in the foothills above the inversion. Not really any changes to
the forecast needed. Bowen
&&
.AVIATION...Offshore flow under strong high pressure aloft will
produce predominantly VFR conditions through 06z Friday. The main
exception to this will be at KEUG where lifr and ifr conditions
will be possible between 09-18z Thursday, but confidence in
duration and timing is low. Suspect KSLE and KUAO will remain
VFR, but there is a smaller chance of some restrictions
developing at these sites in the 12-18z time frame.
PDX AND APPROACHES...Gusty east winds will continue to produce
VFR conditions through 06z Friday. /Neuman
&&
.MARINE...Offshore flow under high pressure aloft will produce
relatively benign conditions across the waters through early next
week. The main exception to this will be gusty east winds from
time to time near gaps in the coastal terrain such as the mouth
of the Columbia River. There is a chance seas could climb towards
10 ft towards the early to middle part of next week. /Neuman
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Air Stagnation Advisory until 10 AM PST Monday for Central
Willamette Valley-Lower Columbia-South Willamette Valley.
High Wind Warning until 6 PM PST Thursday for Western Columbia
River Gorge.
Wind Advisory until 6 PM PST Thursday for Greater Portland
Metro Area.
WA...Air Stagnation Advisory until 10 AM PST Monday for I-5 Corridor
in Cowlitz County.
High Wind Warning until 6 PM PST Thursday for Western Columbia
River Gorge.
Wind Advisory until 6 PM PST Thursday for Greater Vancouver
Area.
PZ...Small Craft Advisory for winds until noon PST Thursday for
Coastal Waters from Cape Shoalwater WA to Florence OR out
60 NM.
&&
Interact with us via social media:
www.facebook.com/NWSPortland
www.twitter.com/NWSPortland
This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. This area is
commonly referred to as the CWA, or forecast area.1 high wind. Local standard time, as filed.
A weather station across the river in Corbett recorded winds up to 48 mph sustained with gusts up to 88 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2017Every state in 2017This day in weather historyWarnings in Washington, December 2017
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: 732694.