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, 3:18 AM PST, 5 hours 17 minutes earlier.
Area Forecast Discussion
National Weather Service Portland OR
317 AM PST Wed Dec 6 2017
.SYNOPSIS...Dry and locally windy weather will persist through the
upcoming weekend as strong high pressure dominates our weather. East
winds will be especially strong in and near the western Columbia
Gorge. Areas outside of the wind will continue to experience cold
nights with overnight temps falling below freezing for most. Valley
fog and low clouds will also persist outside of the windy areas, with
deteriorating air quality due to strong inversions.
&&
.SHORT TERM...Tonight through Friday...East winds are ramping up
through the Columbia Gorge and eastern portions of the PDX metro
area. Peak wind gust so far at KTTD is 35 mph, though sustained winds
are slowly increasing through the 20s. This is occurring as easterly
pressure gradients increase through the Columbia Gorge. Higher
resolution models such as the 4km nested NAM and 1.33km UW WRF-GFS
are more or less on track with KTTD-KDLS gradients now -8.7 mb. High
pressure continues to strengthen east of the Cascades, with MSLPs
nearing 1044 mb over the Columbia Basin.
The only minor surprise thus far has been the depth of the inversion
layer, which has been running around 5000-6000 feet per ESRL's
Troutdale profiler. This is allowing more vertical space for air to
flow through the Gorge, which has thus far kept wind speeds from
reaching advisory/warning criteria in and near the Gorge. However,
the 09z profile seems to be hinting that the top of the inversion is
feeling some downward pressure as our upper level ridge and
subsidence inversion strengthen overhead. Inversion tops appear to be
lowering to 4000 feet per this latest profiler observation, and will
likely continue to lower this morning. As this occurs, expect wind
speeds to increase through the Gorge, and the stronger winds will
become increasingly constricted to areas in and near the Gorge. High
resolution models suggest KTTD-KDLS gradients will increase in
magnitude to around -10 mb this morning, with these gradients
remaining fairly steady through Thursday. So, the existing High Wind
Warning for the west Gorge and Wind Advisory for the east PDX metro
appear to be in good shape, and will make no changes to either with
this morning's package.
Aside from the strong east winds near the Columbia Gorge, the main
forecast issue the next few days will be fog and subfreezing
temperatures. Areas around Eugene have had some dense fog overnight,
but coverage appears to be decreasing over the past couple hours.
Believe this is occurring due to very dry air and east winds 20-30 kt
just above the inversion layer. Fog will probably be very limited
this morning, and the offshore flow will keep all but the lowest few
hundred feet very dry. As a result, plenty of sunshine and seasonable
temps are expected today. Fog may become slightly more widespread
tonight and Thu morning as 950 mb offshore winds decrease south of
Salem, but it will probably take some time for the low level RH to
recover from today. This trend continues into Thu night/Fri, with fog
becoming a bit more widespread away from the western Columbia Gorge.
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 +14 deg C. Meanwhile, areas stuck under inversions,
fog, and stagnant air will likely be below normal with temps
struggling to get out of the 30s during the day and subfreezing
nights. 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 inversions 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. Weagle
.LONG TERM...Friday night through Tuesday...An extended period of
dry weather is likely to continue into early next week 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. It's odd to think of this time of
year, but with the continuation of offshore flow and dry weather, we
may see significant drying of fire fuels.
&&
.AVIATION...Strong high pres aloft and the resultant low-level
offshore flow will yield predominant VFR conditions across the
area through Wed morning. The exception will be the South
Willamette Valley where LIFR to VLIFR conditions exist at 10Z.
Expect gradual improvement in that area Wed morning, but likely
not reaching VFR status until 20-22Z. MVFR cigs will develop in
the Central Columbia River Gorge Wed from about KCZK to K4S2.
PDX AND APPROACHES...VFR SKC through 12Z Thu. East wind 20-25G40
kt at KTTD, with much stronger gusts near the west end of the
Gorge. Weishaar
&&
.MARINE...High pressure and offshore flow will continue for the
next several days. Gusty NE-E wind to continue over the waters,
especially near gaps in coastal terrain through at least Thu.
Have extended the small craft advisory for wind in effect for
PZZ250 and PZZ270 through 18Z Thu. Wind speeds to slowly diminish
late in the week and into the first part of next week.
Seas have fallen below 10 ft, based on the 09Z buoy observations.
Thus, have ended the small craft advisory for hazardous seas.
Wave heights will be in the 4 to 7 ft range Wed night through the
middle of next week. Weishaar
&&
.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 10 AM PST Thursday for
Coastal Waters from Cape Shoalwater WA to Cascade Head OR
out 60 NM.
Small Craft Advisory for Rough Columbia River Bar from 5 AM to
8 AM PST this morning.
&&
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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 strong wind, 1 high wind. Local standard time, as filed.
Strong winds that persisted for several days took a few limbs off trees, took a few shingles off at least one roof, and knocked over a couple fences in the Troutdale area near the Columbia River Gorge. The Troutdale Airport ASOS recorded wind gusts up to 46 mph on 12/8.
Weather station at Corbett High School measured fairly continuous east winds, occasionally measuring to 75 mph+ for a 4-day stretch from the 7th to the 11th. The max wind measured was 48 mph sustained with gusts to 88 mph. Peak winds at Vista House are unknown because the winds blew the sensor off the building. Several trees and some power lines were blown down. One tree fell into a house in Corbett, injuring one person.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2017Every state in 2017This day in weather historyWarnings in Oregon, 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: 732693, 732691.