Heavy snow (up to 20 inches) occurred in the Northern and Central Cascades, mainly in the vicinity of Stevens Pass and Snoqualmie Pass. A Puget Sound Convergence Zone helped augment snowfall amounts.
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.
Heavy snow (up to 20 inches) occurred in the Northern and Central Cascades, mainly in the vicinity of Stevens Pass and Snoqualmie Pass. A Puget Sound Convergence Zone helped augment snowfall amounts.
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 Mar 4, 11:25 PM PST, 3 hours 35 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SEATTLE WA
1125 PM PST WED MAR 4 2009
.SYNOPSIS...AN UPPER LEVEL TROUGH MOVING SOUTHEAST ACROSS BRITISH
COLUMBIA WILL BRUSH WESTERN WASHINGTON WITH A LITTLE LIGHT RAIN AND
MOUNTAIN SNOW TONIGHT AND THURSDAY. RAIN WILL BE DECREASING THURSDAY
BUT A LITTLE CONVERGENCE ZONE ACTIVITY MAY ALLOW RAIN TO PERSIST
OVER PUGET SOUND. AN UPPER LEVEL RIDGE MOVING OVER BRITISH COLUMBIA
ON FRIDAY WILL PRODUCE DRY NORTHERLY FLOW ALOFT AND MOSTLY SUNNY
WEATHER OVER WESTERN WASHINGTON. A COLD FRONT WILL MOVE SOUTHEAST
ACROSS THE AREA EARLY SATURDAY MORNING. A COOL SHOWERY AIR MASS WILL
SETTLE OVER THE AREA THE REST OF THE WEEKEND AS SEVERAL WEAK UPPER
LEVEL TROUGHS MOVE OVERHEAD.
&&
.SHORT TERM...UPDATED ADVISORIES BELOW. RADAR SHOWS AREAS OF LIGHT
RAIN OVER MAINLY THE N INTERIOR THIS EVENING. OBS INDICATE SO FAR IT
HAS MOSTLY BEEN SPRINKLES. GFS/NAM SHOW THE RAIN SHOULD SPREAD S
ACROSS THE REST OF THE AREA OVERNIGHT WITH A BIT MORE
ACCUMULATION...AS THE UPPER LEVEL TROUGH OVER B.C. MOVES SE. IT
LOOKS LIKE THE UPWARD MOTION IS A COMBINATION OF THE UPPER LEVEL
TROUGH...WHICH APPEARS TO BE MAINLY AFFECTING THE NORTH PART OF W
WA...WESTERLY UPSLOPE FLOW OVER THE CASCADES...AND DIVERGENCE ALOFT
CREATED BY THE 120+ KT JETSTREAK THAT IS MOVING S OVER THE AREA.
POPS ARE IN THE LIKELY RANGE FOR TONIGHT SO THE DEVELOPING RAIN IS
COVERED. WITH THE W FLOW AT 850 MB ACROSS THE OLYMPICS...MUCH OF THE
PUGET SOUND REGION WILL BE IN A RAIN SHADOW...SO ANY QPF WILL BE
VERY LIGHT.
BOTH 00Z NAM AND 12Z WRF-GFS SHOW 30-40KT WESTERLY 850 MB WINDS OVER
THE CASCADES TONIGHT...THEN GRADUALLY WEAKENING THURSDAY.
NAM/WRF-GFS BOTH HIT THE SNOW TOTALS FAIRLY HARD...ENOUGH AT THE
PASSES TO JUSTIFY A SNOW ADVISORY. WILL GO WITH THAT IDEA...WITH
BEST ACCUMULATIONS OCCURRING LATE TONIGHT...AND STEVENS PASS GETTING
MORE THAN SNOQUALMIE PASS.
00Z GFS INDICATES THE PRIMARY RAIN PERIOD WILL END BY 18Z WHILE THE
00Z NAM MAINTAINS QPF OVER THE AREA INTO THURSDAY AFTERNOON. THE
EXCEPTION LOOKS LIKE A CONVERGENCE ZONE THAT SHOULD PLAGUE THE PUGET
SOUND REGION INTO EARLY THURSDAY EVENING. SAME CONVERGENCE ZONE
ACTIVITY WILL KEEP THE SNOW GOING AT TIMES OVER THE CENTRAL CASCADES
ON THURSDAY...BUT IT WONT BE ENOUGH TO KEEP THE SNOW ADVISORY GOING
IN THE AFTERNOON...SO WILL RUN IT THROUGH MIDDAY THURSDAY. N WINDS
SHOULD FLUSH THE PSCZ S OF KSEA BY MID-EVENING THURSDAY WITH
ACTIVITY ENDING BY MIDNIGHT.
GFS/ECMWF REMAIN CONSISTENT IN MOVING AN UPPER LEVEL RIDGE OVER B.C.
ON FRIDAY...WITH COOL DRY N FLOW ALOFT KEEPING W WA DRY. SAME N FLOW
SHOULD PRODUCE SUNNY WEATHER...THOUGH HIGH TEMPERATURES WILL BE
ABOUT 5 DEGREES BELOW NORMAL. MODELS ALSO REMAIN CONSISTENT IN
BRINGING A FRONTAL SYSTEM ACROSS THE NE PACIFIC AND OVER W WA EARLY
SATURDAY MORNING. THIS APPEARS TO BE THE FRONT OUT ALONG 170W THIS
EVENING. GFS HAS A FROPA ALONG THE N COAST AROUND 12Z...WHICH MEANS
THE FRONT SHOULD BE THROUGH PUGET SOUND BY MID MORNING. THE MOST
INTERESTING WEATHER LOOKS TO BE BEHIND THE FRONT LATE SATURDAY
THROUGH SUNDAY. 850 MB TEMPS GET COLD ENOUGH TO START THINKING ABOUT
SNOW SHOWERS...AND IT LOOKS LIKE UPWARD MOTION WILL BE PROVIDED BY
ONE OR MORE SHORTWAVE TROUGHS RIDING DOWN OVER THE AREA IN THE N
FLOW ALOFT. KAM
.LONG TERM...PREVIOUS DISCUSSION FROM THE 3 PM AFD...HAVE A BROAD
BRUSH OF SHOWER CHANCES IN THE EXTENDED. MONDAY AND ESPECIALLY
TUESDAY LOOK KIND OF DRY. NEXT SYSTEM IS DUE WEDNESDAY. NOT TOO
CONFIDENT IN THE TIMING. BURKE
&&
.AVIATION...COLD UPPER TROF DIGGING SOUTH THRU B.C. AND ALBERTA HAS
INCREASED THE ONSHORE FLOW INTO WRN WA. PRECIP IS MAINLY OVER SKAGIT
AND SNOHOMISH COUNTY AND WILL SAG SOUTH THRU THURS
MORNING...ENHANCED BY CONVERGENCE OF SLY WIND THRU PUGET SOUND...WLY
WIND THRU THE STRAIT OF JUAN DE FUCA...AND NW WIND DOWN THE STRAIT
OF GEORGIA. KPAE WILL HAVE THE LOWEST CONDITIONS...WITH MVFR CIGS
AND SHOWERS SPREADING SOUTH INTO THE KSEA AREA BY DAYBREAK AND TO
KOLM BY NOON. AMS MOIST AND DESTABILIZING THRU THU MORNING...THEN
DRYING FROM THE NORTH THRU THE AFTERNOON AND EARLY EVENING AS NLY
FLOW DEVELOPS ALF AND ONSHORE SFC FLOW BECOMES NLY AS WELL. 19
KSEA...SW WIND SHOULD SHIFT TO NW AROUND 18Z THU. THERE IS A GOOD
CHANCE OF A STRONG PSCZ THRU THE NIGHT AND THU MORNING AND CIGS AND
VSBY WILL LOWER WHEN THAT SETS UP...DAYBREAK IS A GOOD BET. AMS WILL
BE COLD ALOFT BUT WITH STRONG ONSHORE FLOW I DOUBT THAT ANYTHING
MORE THAN A LITTLE WET SNOW WILL MIX IN AND ONLY INTO THE HEAVIEST
SHOWERS THU...THE SORT OF WET SNOW THAT ONLY A METEOROLOGIST WOULD
NOTICE ON THE WINDSHIELD. IN FACT THE SNOW LEVEL FCST OF 1500 FEET
THU FALLING TO 500 FEET THU NIGHT AS THE SHOWERS DRY UP SEEMS IN THE
BALLPARK SO THERE SHOULD BE NO PROBLEMS WITH WINTER PRECIP WITH THIS
TROF. 19
&&
.MARINE...UPDATED...WITH BOTH SHERINGHAM AND RACE ARND 38KT
SUSTAINED AND A PEAK WIND OF 34KT AT SMITH ADDED 5KTS TO THE FCST
AND UPGRADED THE SMALL CRAFT IN THE STRAIT TO GALE FOR CENTRAL
AND EAST PART. EDIZ HOOK STILL ONLY AT 16KT WHICH IS A LITTLE HARD
TO FIGURE...PROBABLY A GOOD 25-35KT MID CHANNEL AND UIL-BLI PEAKED
AT 4.5MB. WILL ONLY LAST A FEW HOURS THO AND BACK TO SMALL CRAFT AT
3AM. 19
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...SNOW ADVISORY FOR THE NORTH/CENTRAL CASCADES.
WIND ADVISORY ADMIRALTY INLET AREA.
PZ...GALE WARNING CENTRAL STRAIT AND EAST ENTRANCE TO THE STRAIT OF
JUAN DE FUCA...SMALL CRAFT ADVISORY ALL OTHER WATERS.
WEATHER.GOV/SEATTLE
FOR THE ENHANCED AFD PLEASE VISIT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATESTWEBAFD.HTML (ALL LOWERCASE)2 heavy snow. Local standard time, as filed.
Up to 20 inches of snow fell in the Snoqualmie Pass area. The pass was closed for a few hours.
NWAC station at Stevens Pass showed 16 inch snowfall in past 12 hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2009Every state in 2009This day in weather historyWarnings in Washington, March 2009
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: 160696, 164050.