A Pacific frontal system brought heavy snow to the North Cascades.
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 SEW wrote it up.
A Pacific frontal system brought heavy snow to the North Cascades.
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 Seattle, WA wrote its last area forecast discussion before the first event at Dec 26, 3:10 PM PST, 50 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
310 PM PST Mon Dec 26 2016
.SYNOPSIS...A frontal system off the coast will move through the area
tonight bringing rain to the lowlands and heavy snow to the
mountains. Windy conditions are expected tonight, mainly in the
north interior. Showers Tuesday and Tuesday night will decrease
Wednesday. A weaker front will bring rain Thursday. Colder air will
arrive next weekend.
&&
.SHORT TERM...Current IR satellite imagery shows the advertised
front just off the coast...while current radar shows precip ahead of
the front making its way onshore. Latest obs show that the majority
of reporting locations show both temps and dewpoints above 32...so
while an isolated location or two may see a flake here and there
mixed in with their rain at the onset...generally speaking this will
be strictly rain for the lowlands. The exception...of course...being
the Hood Canal area where the prospect of an inch or two of snow
remains on the table. Obs also show southeasterly winds over the San
Juans starting to kick up...and naturally expect this to spread to
remaining locations under wind advisory headline as the afternoon
and evening progress.
Progs remain pretty consistent regarding the frontal passage and the
lingering shortwave feature behind it...as such...left much of the
near term forecast and associated headlines alone for the afternoon
forecast package. Things also continue to look on track for weak
upper level ridge to build into the area Wednesday resulting in a
bit of a break from precip for late Wednesday morning into Wednesday
afternoon. A frontal system associated with an upper level low that
is currently progged to remain well north of W WA looks to bring a
return to precip Wednesday night...becoming more widespread
Thursday. SMR
.LONG TERM...As the aforementioned upper level low moves eastward
and fizzles out...moisture looks to remain in place over W WA
Thursday evening before slowly tapering off overnight. A
secondary...stronger upper level low is expected to dive down into
CA...leaving conditions here generally dry for Friday and into early
Saturday afternoon. That being said...as this system does dive
south...W WA will likely see cooler temperatures in its wake and a
follow-up system looks to bring some moisture into the area. This
could result in the potential for either mixed precip or snow in the
lowlands late Saturday afternoon and into Sunday. Sure...it is a bit
out there temporally but given model agreement...which to be frank
is rather shocking to see given prior model squabbles...there may be
some minor variations but hard to discount at this time. SMR
&&
.AVIATION...A strong Pacific frontal system will move through
Western Washington this evening, followed by strong westerly flow
tonight and Tuesday. At the surface, increasing southeasterly
pressure gradients this evening, will switch to onshore flow
behind the front. The air mass is moist and stable, becoming
weakly unstable Tuesday afternoon.
At 2 pm conditions were low-end VFR to locally MVFR with SCT-
BKN018 OVC045-060 and rain beginning to spread inland ahead of the
approaching front. Rain will increase during the next few hours
with conditions deteriorating to widespread MVFR and locally IFR.
That should continue tonight and Tuesday in moist onshore flow
behind the front.
KSEA...Southeast wind 6-12 kt becoming south 10-18 kt in the next
couple hours. Rain this evening, will give way to showers
overnight and Tuesday, but conditions will not improve much in
moist onshore flow. McDonnal
&&
.MARINE...A vigorous Pacific frontal system will move through the
coastal waters this evening and quickly across Western Washington.
Gale warnings are in effect through midnight for the coastal
waters, east entrance Strait of Juan de Fuca, Admiralty Inlet,
and the northern inland waters. Small craft advisories are in
effect for the remainder of the waters. Strong post frontal
onshore flow with small craft advisory winds will follow the front
later tonight through Tuesday into Tuesday night. The low level
flow will switch to offshore on Wednesday. Another, slightly
weaker front will arrive Thursday. Another strong front will
approach the region from the northwest Saturday. McDonnal
&&
.HYDROLOGY...No flooding is expected over the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Warning until 6 AM PST Wednesday for Cascades of
Pierce and Lewis Counties-Cascades of Snohomish and King
Counties-Cascades of Whatcom and Skagit Counties-Olympics.
Winter Weather Advisory until midnight PST tonight for Bremerton
and Vicinity-Hood Canal Area.
Wind Advisory until 4 AM PST Tuesday for Admiralty Inlet Area-
San Juan County-Western Skagit County-Western Whatcom
County.
PZ...Small Craft Advisory for rough bar from midnight tonight to 6 AM
PST Wednesday for Grays Harbor Bar.
Small Craft Advisory from midnight tonight to 6 AM PST Wednesday
for Coastal Waters From Cape Flattery To James Island 10 To
60 Nm-Coastal Waters From Cape Flattery To James Island Out
10 Nm-Coastal Waters From James Island To Point Grenville
10 To 60 Nm-Coastal Waters From James Island To Point
Grenville Out 10 Nm-Coastal Waters From Point Grenville To
Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point
Grenville To Cape Shoalwater Out 10 Nm.
Gale Warning until midnight PST tonight for Coastal Waters From
Cape Flattery To James Island 10 To 60 Nm-Coastal Waters
From Cape Flattery To James Island Out 10 Nm-Coastal Waters
From James Island To Point Grenville 10 To 60 Nm-Coastal
Waters From James Island To Point Grenville Out 10 Nm-
Coastal Waters From Point Grenville To Cape Shoalwater 10
To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater Out 10 Nm.
Small Craft Advisory until 3 PM PST this afternoon for Admiralty
Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca-
Northern Inland Waters Including The San Juan Islands.
Small Craft Advisory from midnight tonight to midnight PST
Tuesday night for East Entrance U.S. Waters Strait Of Juan
De Fuca-Northern Inland Waters Including The San Juan
Islands.
Gale Warning until midnight PST tonight for Admiralty Inlet-East
Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
Waters Including The San Juan Islands.
Small Craft Advisory until 3 AM PST Wednesday for Central U.S.
Waters Strait Of Juan De Fuca-West Entrance U.S. Waters
Strait Of Juan De Fuca.
Small Craft Advisory from midnight tonight to 6 AM PST Tuesday
for Admiralty Inlet.
Small Craft Advisory from 6 PM this evening to 1 PM PST Tuesday
for Puget Sound and Hood Canal.
&&
www.weather.gov/seattle
You can see an illustrated version of this discussion at
www.weather.gov/seattle/gafd/latest_webafd.html1 heavy snow. Local standard time, as filed.
Mt Baker NWAC site recorded 18 inches in 24 hours ending 2 pm Tue Dec 27, and 24 inches total.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2016Every state in 2016This day in weather historyWarnings in Washington, December 2016
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: 666365.