Strong cyclonic flow was present over the Pacific Northwest on February 25, with a strong jet streak in place at 250mb to aid in ascent as several small perturbations affected the region within the strong cyclonic flow. This would be sufficient to help enhance snowfall over the 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.
Strong cyclonic flow was present over the Pacific Northwest on February 25, with a strong jet streak in place at 250mb to aid in ascent as several small perturbations affected the region within the strong cyclonic flow. This would be sufficient to help enhance snowfall over the 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 Feb 25, 4:14 AM PST, 2 hours 46 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
414 AM PST Thu Feb 25 2021
.SYNOPSIS...Cold front moving through Western Washington today.
Behind the front a cool and unstable airmass will move over the
area and remain through Friday. Strong westerly winds aloft will
create strong orographics in the mountains resulting in heavy snow
through at least Friday morning. Short break in the weather
Saturday before a series of weak systems bring a chance of rain at
times through the middle of next week.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...Satellite imagery shows
cold front moving through Vancouver Island early this morning.
Rain out ahead of the front spread over the area overnight.
Temperatures at 3 am/11z were in the mid 30s to lower 40s.
Front moving through Western Washington this morning with steady
precipitation giving way to showers in the lowlands. A little bit
of cool air trapped over the Kitsap peninsula with snow levels
around 500 feet early this morning. Snow levels will rise to above
1000 feet by mid morning. Windy conditions with and behind the
front with wind advisories for the coast and northern portions of
the interior. Strong post frontal westerlies will quickly develop
late this morning and continue for the remainder of the day. A
high wind warning has been issued for the Admiralty Inlet area
which includes Whidbey Island for sustained west winds as high as
40 mph with gusts as high as 60 mph. In addition to the winds at
the surface, westerly 850 mb winds will increase to 30 to 40
knots. The resulting strong orographics in the mountains will
result in heavy snow for all mountain locations. The west
northwesterly direction of the 850 mb winds will favor the Central
Washington Cascades for the highest snow amounts ( Snoqualmie
Pass once again ). Snow levels will be around 2000 feet. The
winter storm warning for the Cascades will continue today with an
advisory for the Olympics. With the destabilizing air mass and
strong convergence developing there is a chance of thunderstorms
near the east entrance of the Strait of Juan de Fuca into
Snohomish county this afternoon and evening. Highs today in the
mid 40s.
Cool unstable air mass remaining over Western Washington tonight
into Friday. Strong orographic flow continuing with west
northwesterly 850 mb winds as strong as 50 knots overnight into
Friday morning. Heavy snow continuing in the Cascades. Favored
locations in the Central Cascades could see as much a 3 and a
half feet of new snow by late Friday afternoon. For the lowlands
shower activity continuing with the flow aloft rain shadowing the
Central Puget Sound at times. With the strong winds aloft and
good mixing of the lower levels of the air mass due to the
instability windy conditions continuing into Friday morning. High
wind warning continuing until 10 am for the Admiralty Inlet area
with windy conditions over the remainder of the area. Lows tonight
near 40 with highs Friday in the mid and upper 40s.
Last shortwave embedded in the northerly flow aloft moving through
Western Washington Friday night and early Saturday morning.
Snow rates easing in the mountains with winds easing in the
lowlands. Shower activity coming to an end during the day
Saturday for a short dry spell. Lows in the mid 30s to lower 40s
with highs in the mid and upper 40s.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Extended model solutions
not showing much consistency this morning with the GFS keeping a
ridge over the area Sunday into Monday for a couple of mostly dry
days while the ECMWF is much weaker with the ridge and brings an
upper level low down into the area Monday. Ensembles are not much
help with solutions in both models supporting the operational run
solutions. Previous forecast leaned toward the ECMWF and have no
reason to change it this morning. The inconsistencies in the
models continue for days 6 and 7 with the GFS staying with a ridge
while the ECMWF brings weak systems down out of the northwest
over the area. Once again the ensemble solutions support the
operational runs. With broadbrush days 6 and 7 with a chance of
rain forecast. Temperatures will continue to be a little below
normal through the period.
&&
.AVIATION...Frontal system currently moving inland across Western
Washington this morning, with radar showing the heaviest rain
associated with the system currently along the Olympic Peninsula
and tracking eastward. Overall, expect widespread rain to continue
to move inland through the early morning hours, with lowering
ceilings and visibilities. Current conditions across most area
terminals are primarily MVFR, though some sites have dropped to
IFR to LIFR with the heavier precipitation. Winds from the south
have started to pick up overnight and will gradually shift to the
west/southwest this morning in the wake of the frontal passage.
Overall, expect winds to remain gusty through much of the day,
especially for sites like KBLI, KPAE, and KHQM (with sustained
winds generally 10-25kt, gusts to 25-35kt). Localized gusts to
30-40 kt will also be possible at times for terminals along the
coast and across the northern interior. Expect widespread rain to
taper to scattered showers by the late morning hours. With strong
post-frontal winds, will likely see a convergence zone develop
this afternoon over Snohomish county. Precipitation in showers
could be heavy at times, especially in the vicinity of the PSCZ,
and will temporarily reduce visibility and could produce some
small hail.
KSEA...MVFR this morning, with ceilings likely to continue
dropping to IFR as the heavier precipitation with the frontal
system moves in over the next few hours. Rain will taper to
convective showers by late morning, though ceilings may have a
hard time recovering back to VFR. A strong PSCZ will be possible
this afternoon and evening and could briefly lower ceilings and
visibilities should it make it all the way southward in the
vicinity of the terminal. Winds will be S 8-12kts through the
early morning, increasing to 10-15 kt out of the W/SW later this morning
and afternoon. Gusts to 20-30 kts possible at times. 14
&&
.MARINE...Frontal system moving through the waters this morning
with strong post frontal onshore flow continuing into Friday.
Gale warnings are up for a majority of the waters through at least
Friday morning. Winds late Friday into Friday night. Much weaker
system moving through the waters Friday night into Saturday
morning. Additional weak systems are possible into the middle of
next week.
Swell increasing behind the front today and by tonight seas in the
20 to 22 foot range forecast. Seas in the low 20 foot range will
continue until late Friday afternoon. Felton
&&
.HYDROLOGY...The Chehalis at Porter crested Wednesday below flood
stage. The flood watch for Grays Harbor county has come to an end.
Flooding is not expected on any of the other rivers in the next 7
days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Warning until 10 PM PST Friday for Cascades of
Pierce and Lewis Counties-Cascades of Snohomish and King
Counties-Cascades of Whatcom and Skagit Counties.
Wind Advisory until 4 PM PST this afternoon for Central Coast-
North Coast-San Juan County-Western Skagit County-Western
Whatcom County.
Flood Watch until 4 AM PST early this morning for Central Coast-
Lower Chehalis Valley Area-Olympics.
High Surf Advisory from 10 PM this evening to 4 PM PST Friday
for Central Coast-North Coast.
High Wind Warning from 10 AM this morning to 10 AM PST Friday
for Admiralty Inlet Area.
Winter Weather Advisory until 10 AM PST Friday for Olympics.
Wind Advisory until 10 AM PST this morning for Admiralty Inlet
Area.
PZ...Small Craft Advisory from 9 AM this morning to 4 PM PST Friday
for Grays Harbor Bar.
Gale Warning until 10 AM PST Friday for Admiralty Inlet-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 4 PM PST Friday for East Entrance U.S. Waters
Strait Of Juan De Fuca.
Gale Warning until 10 PM PST this evening for Northern Inland
Waters Including The San Juan Islands.
Small Craft Advisory until 1 PM PST this afternoon for Central
U.S. Waters Strait Of Juan De Fuca-West Entrance U.S.
Waters Strait Of Juan De Fuca.
Gale Warning from 1 PM this afternoon to 4 PM PST Friday for
Central U.S. Waters Strait Of Juan De Fuca-West Entrance
U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory until 4 PM PST Friday for Puget Sound and
Hood Canal.
&&
www.weather.gov/seattle1 heavy snow. Local standard time, as filed.
Snow noticeably began to pick up across the Central Cascades shortly after midnight on February 25th and continued through daybreak on the 26th. During a 24 hour period from roughly 7am on the 25th to 7am on the 26th, Stevens Pass reported around 20 inches if new snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2021Every state in 2021This day in weather historyWarnings in Washington, February 2021
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: 945334.