A vigorous Pacific frontal system brought heavy snow to the Washington 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 vigorous Pacific frontal system brought heavy snow to the Washington 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 Nov 21, 4:14 PM PST, 1 hour 46 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
414 PM PST MON NOV 21 2011
.SYNOPSIS...WET AND UNSETTLED CONDITIONS WILL PERSIST THROUGH
WEDNESDAY DUE TO A VERY MOIST FRONTAL BOUNDARY STALLING OVER THE
AREA. IN ADDITION TO LOCALLY HEAVY PRECIPITATION...ANTICIPATE
STRONG WINDS ACROSS MUCH OF THE AREA OVERNIGHT INTO TUESDAY MORNING.
ALAS...A COLDER PACIFIC STORM IS EXPECTED TO BEGIN IMPACTING THE
REGION ON THURSDAY.
&&
.SHORT TERM...
PRECIP HAS INCREASED ACROSS THE AREA LATE TODAY AND WILL BECOME
LOCALLY HEAVY AT TIMES OVERNIGHT...ESPECIALLY ON THE S AND SW FACING
SLOPES OF THE OLYMPICS AND CASCADES. IN ADDITION TO PERIODS OF HEAVY
PRECIP...WINDS WILL INCREASE OVERNIGHT AHEAD A STRONG CDFNT. THIS
FRONT WILL SWEEP ACROSS THE CWA TOMORROW MORNING BEFORE STALLING.
THE STRONGEST WINDS WILL OCCUR OVER THE COAST...OLYMPICS...AND NW
INTERIOR WHERE HIGH WIND WARNINGS ARE IN EFFECT. ELSEWHERE...ACROSS
THE LOWLANDS...ANTICIPATE SLY WINDS INCREASING INTO THE ADVISORY
CRITERIA RANGE.
CONCERNING SNOW IN THE MOUNTAINS...EXTENDED THE WINTER WEATHER
ADVISORY FOR SNOW THROUGH TONIGHT FOR THE OLYMPICS AND CENTRAL
CASCADES. THE PRECIP WILL FALL AS SNOW IN THE CENTRAL CASCADE PASSES
TONIGHT BUT WILL QUICKLY CHANGE OVER TO RAIN TUE MORNING IN RESPONSE
TO MILD...WLY FLOW PUSHING THRU THE PASSES. THE COLD AIR WILL LINGER
A BIT LONGER OVER THE N CASCADES WHERE 1-2 FT OF SNOW IS LIKELY BY
LATE TUE...HENCE THE WINTER STORM WARNING.
THE MODELS WERE IN AGREEMENT THAT A BAROCLINIC BAND /FEATURING
COPIOUS MOISTURE EMANATING FROM THE SUBTROPICS/ WILL STALL OVER THE
REGION DURING THIS PERIOD. EXACTLY WHERE IT WILL STALL WAS STILL A
QUESTION DUE TO WAVES ANTICIPATED ALONG THE FRONTAL BOUNDARY. THUS
EXPECT PERIODS OF LOCALLY HEAVY PRECIP OVER MAINLY THE SW FACING
SLOPES OF THE OLYMPICS AND CASCADES TO PERSIST THRU AT LEAST WED.
EXPECT THE BAROCLINIC ZONE TO WEAKEN WED NIGHT...WITH THE FOCUS OF
THE HEAVIEST PRECIP SHIFTING MAINLY S OF THE CWA BY THU MORNING.
ALAS...A COLDER SYSTEM WILL BEGIN TO IMPACT THE REGION THU
AFTERNOON. IF THIS SYSTEM ENDS UP AS WET AS THE MODELS WERE
ADVERTISING...A WINTER STORM WATCH WILL BE NEEDED FOR THE MOUNTAINS
THU AFTERNOON AND NIGHT.
.LONG TERM...
A WET AND UNSETTLED PATTERN WILL PERSIST OVER THE PAC NW DUE TO A
STRONG JET SENDING A SERIES OF STORM SYSTEMS ACROSS THE REGION.
&&
.HYDROLOGY...THERE ARE TWO FRONTAL SYSTEMS PRESENTING A THREAT OF
FLOODING ON WESTERN WASHINGTON RIVERS IN THE SHORT TERM. THE FIRST
SYSTEM WILL MOVE THROUGH THE AREA TONIGHT AND TUESDAY...BRINGING
PRECIPITATION AMOUNTS OF 2 TO 6 INCHES TO THE MOUNTAINS. SOME MODEL
RUNS HAVE SHOWN SLIGHTLY HEAVIER BULLSEYES...BUT THIS RANGE LOOKS
REPRESENTATIVE FOR THE 24 HR EVENT. SNOW LEVELS WILL RISE TO 5000 TO
6000 FT. THE HEAVIEST AMOUNTS WILL BE OVER THE OLYMPIC MOUNTAINS --
ALSO WHERE THE SNOW LEVEL WILL RISE FIRST -- WITH A SECONDARY FOCUS
OVER THE CENTRAL AND SOUTHERN CASCADES AND THE SOUTHWEST PART OF
WESTERN WASHINGTON.
THE SECOND FRONTAL WAVE WILL MOVE THROUGH TUESDAY NIGHT AND
WEDNESDAY...WITH ANOTHER 1 TO 4 INCHES OF PRECIPITATION. THE SNOW
LEVEL WILL BE IN THE 3000 TO 4000 FT RANGE. THERE IS MORE
UNCERTAINTY ABOUT THE FOCUS OF HEAVIEST PRECIPITATION FOR THE SECOND
WAVE...AS MODELS HAVE BEEN SOMEWHAT INCONSISTENT. MOST LIKELY
THOUGH...IT WILL BE SIMILAR TO THE FIRST WAVE.
AT THIS TIME...THE SCENARIO APPEARS TO PRESENT A THREAT OF FLOODING
FOR ONLY THE MOST FLOOD-PRONE RIVERS OF WESTERN WASHINGTON. AND --
WITH THE POSSIBLE EXCEPTION OF THE SKOKOMISH RIVER -- THE FLOODING
THAT DOES OCCUR SHOULD BE RELATIVELY MINOR.
THE FLOOD WATCH AREA HAS BEEN EXPANDED TO INCLUDE LEWIS AND THURSTON
COUNTIES...WHERE MINOR FLOODING IS POSSIBLE ON THE NEWAUKUM AND
CHEHALIS RIVERS. IT ALSO NOW INCLUDES PIERCE...KING AND SNOHOMISH
COUNTIES WITH MINOR FLOODING POSSIBLE ON THE PUYALLUP RIVER NEAR
ORTING...AND THE SNOQUALMIE AND STILLAGUAMISH RIVERS.
THE FLOOD WATCH REMAINS IN EFFECT FOR THE OLYMPIC PENINSULA. THE
SKOKOMISH RIVER WILL MOST LIKELY FLOOD. THE OTHER RIVER OF PRIMARY
CONCERN THERE IS THE ELWHA...IN PART DUE TO UNCERTAINTY IN ITS
BEHAVIOR SINCE THE DAM THERE HAS BEEN REMOVED RECENTLY.
FINALLY IT SHOULD BE NOTED THAT A SCENARIO LIKE THIS...WITH
PRECIPITATION ARRIVING IN MULTIPLE SYNOPTIC WAVES...DO LEAVE A
HIGHER DEGREE OF UNCERTAINTY. THE BOTTOM LINE THEN IS STAY TUNED FOR
UPDATES AND REVISIONS TO THE FORECAST. MCDONNAL
&&
.AVIATION...A VERY STRONG FRONT OVER THE OFFSHORE WATERS WILL MOVE
INLAND TUE MORNING. THE AIR MASS WILL BE MOIST AND SOMEWHAT STABLE
TONIGHT THEN BECOME MOIST AND SOMEWHAT UNSTABLE BUILD THE FRONT TUE
MORNING. EXPECT MAINLY MVFR CIGS AND VISIBILITIES THROUGH TUESDAY
AS PRECIPITATION SPREADS IN AHEAD OF THE INCOMING FRONT. MVFR
CONDITIONS WILL DOMINATE IN POST FRONTAL SHOWERS TUESDAY.
THE MAIN ISSUE TONIGHT THROUGH EARLY TUE MORNING WILL BE VERY STRONG
WINDS ALOFT WITH THE INCOMING FRONTAL SYSTEM. SW WINDS WILL RISE TO
50 KT AT 2000 FEET AHEAD OF THE FRONT AND TO 70-80 KT AT 5000 FT.
THE MAIN SURFACE FRONT WILL MOVE TO THE SOUTH OF THE AREA DURING THE
MORNING TUESDAY. BUT EXPECT STRONG WINDS TO CONTINUE TO OVERRUN THE
SURFACE FRONT THROUGH TUESDAY NIGHT OR EARLY WEDNESDAY. AHEAD OF THE
FRONT TONIGHT AND EARLY TUE...EXPECT THE STRONG WIND TO INTERACT
WITH THE TERRAIN CAUSING AREAS OF WIND SHEAR WITH OTHER AREAS SEEING
STRONG GUSTS TO 50 KT REACHING THE SURFACE ALONG THE COAST AND IN
THE INTERIOR NORTH OF EVERETT.
KSEA...GENERALLY EXPECT 5SM -RA BR BKN020 OVC035 TO DOMINATE TONIGHT
THRU TUE MORNING. S WIND 8-12 KT WILL INCREASE TO 15-25 KT AFTER 03Z
AND 22G35 KT AFTER 10Z. WIND AT 020 SW 50 KT AT 030 AND SW 75 KT AT
050 BY 10Z TUE AND CONTINUING THROUGH TUE MORNING. ALBRECHT
&&
.MARINE...A VERY STRONG FRONT WILL MOVE THROUGH THE COASTAL WATERS
LATE TONIGHT AND THROUGH THE INLAND WATERS TUE MORNING. EXPECT STORM
FORCE WINDS TO DEVELOP IN THE COASTAL WATERS THIS EVENING. FREQUENT
STORM FORCE WIND GUSTS ARE EXPECTED TO DEVELOP AT THE EAST ENTRANCE
TO THE STRAIT AND IN THE NORTHERN INLAND WATERS LATER THIS EVENING
AND CONTINUE THROUGH TUESDAY MORNING. THE OTHER WATERS WILL SEE GALE
FORCE WINDS TONIGHT INTO TUE MORNING AHEAD OF THE FRONT.
SEAS ALONG THE COAST WILL BUILD TO 20-25 FT LATER TONIGHT THROUGH
TUE MORNING.
ANOTHER STRONG FRONT WILL MOVE THROUGH THE WATERS THU. THIS FRONT
WILL BRING WIDESPREAD GALES TO THE COASTAL AND NORTHERN INLAND
WATERS. ADDITIONAL STRONG FRONTS WILL IMPACT THE WATERS THIS
WEEKEND. ALBRECHT
&&
.AVALANCHE...A STRONGER...WARMER...AND WETTER SYSTEM IS SET TO HIT
THE MOUNTAINS OVERNIGHT THROUGH TUESDAY NIGHT...WITH SIGNIFICANT
WATER AT RISING FREEZING LEVELS AND VERY STRONG WINDS. THIS WEATHER
SHOULD TIP THE BALANCE IN THE CURRENTLY FRAGILE SNOWPACK. EARLY COLD
LOW DENSITY SNOW AND A VARIETY OF WEAK LAYERS SHOULD BE NO MATCH FOR
WHAT'S COMING. WIDESPREAD NATURAL AVALANCHES ARE CERTAIN AND SOME
LARGE AND VERY DANGEROUS SLIDES POSSIBLE...ESPECIALLY IN AREAS NEAR
AND WEST OF THE CREST, THE OLYMPICS, THE VOLCANOES AND THE NORTHEAST
CASCADES ABOVE ABOUT 5000 FEET WHERE A DEEPER EARLY SEASON SNOWPACK
EXISTS. AN AVALANCHE WARNING IS IN EFFECT WITH THE AVALANCHE DANGER
LEVEL EXPECTED TO RISE TO EXTREME...THE HIGHEST LEVEL IN MANY AREAS
OVERNIGHT AND TUESDAY. AVALANCHE TERRAIN SHOULD BE AVOIDED THROUGH
TUESDAY IN THESE AREAS. MORE DETAILS AT NWAC.US
KRAMER
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...HIGH WIND WARNING FROM 7 PM THIS EVENING TO NOON PST TUESDAY
FOR THE COAST...OLYMPICS...AND NORTHWEST INTERIOR.
WINTER STORM WARNING ABOVE 3500 FEET UNTIL 6 PM PST TUESDAY
FOR THE WEST SLOPES OF THE NORTH CASCADES.
WIND ADVISORIES ARE IN EFFECT FOR THE REST OF THE LOWLANDS
FROM 7 PM THIS EVENING TO NOON PST TUESDAY.
WINTER WEATHER ADVISORY ABOVE 4000 FEET UNTIL 6 AM PST TUESDAY
FOR THE OLYMPICS AND CENTRAL CASCADES.
FLOOD WATCHES ARE IN EFFECT FOR MUCH OF THE AREA FROM TUESDAY
MORNING THROUGH LATE WEDNESDAY NIGHT.
PZ...STORM WARNING ARE IN EFFECT UNTIL NOON PST TUESDAY FOR THE
COASTAL WATERS...EAST ENTRANCE TO THE STRAIT OF JUAN DE
FUCA...AND THE NORTHERN INLAND WATERS.
GALE WARNINGS ARE IN EFFECT UNTIL NOON PST TUESDAY FOR THE
REMAINING WATERS.
SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 4 AM PST WEDNESDAY
FOR THE GRAYS HARBOR BAR.
&&
WWW.WEATHER.GOV/SEATTLE2 heavy snow. Local standard time, as filed.
USFS NWAC station at Stevens Pass Ski Area had 18 inches of snow, Alpental had 20 inches, Snoqualmie Pass had 18 inches, Paradise had 20 inches.
USFS NWAC station at Mt Baker reported 18 inches of snow, Washington Pass had 12 inches, Stevens Pass Ski Area 18 inches.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2011Every state in 2011This day in weather historyWarnings in Washington, November 2011
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: 358455, 358454.