Snow began falling in the Cascades on Saturday, February 4, then develop over the Western Washington lowlands on Sunday, February 5, and continued into Monday, February 6. Snow amounts over the lowlands varied widely, from less than an inch in locations near large bodies of water to more than a foot over higher terrain.
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.
Snow began falling in the Cascades on Saturday, February 4, then develop over the Western Washington lowlands on Sunday, February 5, and continued into Monday, February 6. Snow amounts over the lowlands varied widely, from less than an inch in locations near large bodies of water to more than a foot over higher terrain. The storm resulted in snowy and icy roads, widespread power outages, and closures of schools and businesses.
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 Feb 4, 9:50 AM PST, 2 hours 10 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
950 AM PST Sat Feb 4 2017
.SYNOPSIS...A cold upper level low offshore will maintain cool moist
southwest flow aloft over Western Washington through Sunday for
periods of rain and possibly some spotty light snow on higher hills
on Sunday. The low will weaken and move across the area Monday
morning with light snow likely. Another low will keep the air mass
cold with scattered rain or snow showers on Tuesday. A warm front
will bring rain and warmer conditions Wednesday night and Thursday.
&&
.SHORT TERM...The cold upper level low was offshore near 48N/133W
this morning with southwest flow aloft over W WA. Bands of moisture
wrapping around the low will be moving inland across W WA this
weekend in the SW flow aloft. Snow levels should be around 2000 feet
today, except for western Whatcom County, which means all
precipitation today will be rain. NE Fraser River valley outflow is
keeping temperatures over Whatcom county near or below freezing and
the layer of sub-freezing air is shallow, so a mix of light snow,
light freezing rain and light rain can be expected probably through
tonight. A Winter Weather advisory has been issued to address the
mix. SW flow aloft will continue to bring snow to the Cascades,
where an advisory is in effect through tonight.
The Fraser river valley outflow is currently weakening with the BLI-
YWL pressure gradient down to -10.5 MB, so locally windy conditions
will diminish through the day.
The upper level low will begin moving slowly E tonight and will be
near the northern tip of Vancouver Island early Sunday morning. Snow
levels will lower as the cold air with the low approaches the area
down to 500-1000 feet over the N interior and around 1000 feet over
the rest of the interior. This is low enough so that some light snow
may be mixed in with the rain over higher hills, especially in the
afternoon.
The upper level low will weaken into an upper level trough Sunday
night, then move E across the area Monday morning. Snow levels will
drop to near sea level as increasing Fraser river valley outflow
combines with the cold air aloft in the trough. Fortunately, the
trough doesn't look like a big precipitation producer, but there
should be enough precipitation for up to 3 inches of snow late
Sunday night through Monday. GEFS plume plots for snow support these
amounts.
The increasing Fraser river valley outflow will increase again with
borderline high winds possible. The 12Z GFS forecasts the BLI-YWL
gradient getting up to -20.4 MB at 09Z Monday. The NAM is at -18.4
MB. A high wind watch will be considered for the afternoon package.
Kam
.LONG TERM...Previous discussion...As the upper low crosses the area
through the day Monday...the precip signature over the area looks to
thin out some.
This will not completely dispel the chances of precip...but may
allow for a slight breather before the next weak round pushes into
the area Monday night and into Tuesday as a secondary trough moves
through. Wednesday hints at a slight break in the action during the
afternoon and early evening hours as a meager upper level ridge
provides the briefest of succor. In its wake is a good news/bad news
situation: the good news is that temperatures warm up with daytime
highs approaching 50...the bad news is it is going to be awfully
rainy...with some impressive QPF amounts over the area. This may
need to be monitored for potential hydrologic concerns...but that is
still pretty far out yet. SMR
&&
.AVIATION...A deep upper low near 48N 134W will drift slowly
eastward and maintain strength over the next 24 hours. This will
lead to strong southwest-west flow aloft over western Washington.
A cold front will push inland this afternoon, accompanied by a
band of heavier rain and lower cigs. The front will be followed
tonight by post-frontal convective showers owing to colder air
aloft. Cigs and vsbys should improve some later tonight, mainly
due to a little lifting of the cigs in the more unstable post-
frontal air mass.
KSEA...A cold front arriving from the Pacific early this evening
will be preceded by several hours of enhanced rain and IFR cigs
this afternoon. Southerly winds will be a bit gusty behind the
front this evening, gusts around 20-25 kt. Cigs may lift into the
020-030 range overnight in the more unstable air mass behind the
front, but scattered showers will continue to move past the
terminal. Haner
&&
.MARINE...A surface trough and cold front will sweep inland late
this afternoon and this evening, followed by a brief surge of
strong southwest gradients. This will lead to small-craft strength
southerlies through Puget Sound, as well as a surge of westerlies
through the Strait and into the northern inland waters tonight.
A fairly weak low will move southeast from the offshore waters
across southwest Washington Sunday night and Monday. This will
initiate stronger northerly flow across the forecast area, with
Fraser outflow winds over the northern part of the forecast area
-- probably gale force in the northern inland waters around Sunday
night and Monday morning. Just issued a Gale Watch to give proper
lead time for the possibility of that occurrence.
Current forecasts indicate that a fairly vigorous Pacific frontal
system could reach the area late Wednesday, with gale southerlies
over the coastal waters and in the western Strait of Juan de Fuca.
Current model runs don't really support this idea, but models in
the longer range have been showing poor agreement and run-to-run
consistency. Haner/McDonnal
&&
.HYDROLOGY...No river flooding expected for the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory until 4 AM PST Sunday for
Western Whatcom County.
Winter Weather Advisory until 4 AM PST Sunday for Cascades of
Pierce and Lewis Counties-Cascades of Snohomish and King
Counties-Cascades of Whatcom and Skagit Counties.
PZ...Small Craft Advisory until 3 PM PST Sunday 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 from 6 PM this evening to 3 AM PST Sunday
for Central U.S. Waters Strait Of Juan De Fuca-East
Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Watch from Sunday afternoon through Monday afternoon for
Northern Inland Waters Including The San Juan Islands.
Small Craft Advisory until 3 AM PST Sunday for Northern Inland
Waters Including The San Juan Islands.
Small Craft Advisory from 3 PM this afternoon to 3 AM PST Sunday
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.html14 heavy snow. Local standard time, as filed.
Stevens Pass NWAC station reported 18 inches snow during the warning period ending at 3 am Feb 5. Alpental NWAC station reported 13 inches snow during 12 hours ending 3 am Feb 5. Snoqualmie Pass NWAC station reported 14 inches snow during 12 hours ending 3 am Feb 5.
Paradise NWAC station reported 14 inches snow during 12 hours ending 3 am Feb 5.
Four CoCoRaHS stations and two NWS spotters reported 4.0 to 4.7 inches snow during the 12 hours ending 7 am Feb 5.
Paradise NWAC station reported 19 inches snow during 24 hours ending 4 am Feb 6.
NWS spotters reported 4.0 to 5.0 inches snow during the warning period.
Numerous NWS spotters reported snowfall ranging from 4 to 15 inches across the zone during the warning period.
Numerous NWS spotters reported snowfall ranging from 4 to 13 inches across the zone during the warning period.
Several NWS spotters reported snowfall ranging from 4 to 11 inches across the zone during the warning period.
Numerous NWS spotters reported snowfall ranging from 4 to 8 inches across the zone during the warning period.
Numerous NWS spotters reported snowfall ranging from 5 to 9 inches across the zone during the warning period.
Two CoCoRaHS stations and an NWS spotter reported snowfall ranging from 4 to 6 inches across the zone during the warning period.
Three CoCoRaHS stations and an NWS spotter reported snowfall ranging from 4 to 5 inches across the zone during the warning period.
Several NWS spotters reported snowfall ranging from 4 to 8 inches across the zone during the warning period.
Five CoCoRaHS stations reported 4.0 to 5.6 inches snow during the 12 hours ending 7 am Feb 6.
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, February 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: 677545, 677546, 677548, 677547, 677551, 677552, 677553, 677554, 677556, 677558, 677559, 677557, 677560, 677549.