An upper level trough Gulf Low continued off the west coast that brought a series of atmospheric rivers resulting in flooding across parts of western Washington. This second atmospheric river episode of the month was a set of three atmospheric rivers back-to-back-to-back.
Every event with a place to put it. Tap one for its entry below.
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.
An upper level trough Gulf Low continued off the west coast that brought a series of atmospheric rivers resulting in flooding across parts of western Washington. This second atmospheric river episode of the month was a set of three atmospheric rivers back-to-back-to-back. Water vapor transport into Western Washington averaged 160 - 200% of normal during the period of 11 November - 16 November. Heavy rainfall spread across the region on the night of the 11th through November 12, with the heaviest rain starting across Southwest Washington and slowly shifting to the north through the day. Rainfall totals ranged from 5 to 10 inches in spots leading to areal and river flooding, including major flooding. |Heavy, persistent rainfall associated with the Atmospheric River shifted northward across Western Washington on November 13 before stalling over northwest Washington November 14 through 16. Another 5 to 10 inches of rainfall fell across the northern half of western Washington. The snow level rose to 8000 to 10,000 feet, resulting in some snow melt contributing to runoff. Widespread minor or greater flooding occurred. Major flooding occurred on the Bogachiel, the three forecast points on the Nooksack, Skagit, and Cowlitz Rivers. Moderate flooding occurred on the Elwha, Skokomish, Skykomish, Snohomish, Snoqualmie, Puyallup, Nisqually, Newaukum Rivers and South Prairie Creek. Preliminary record flows occurred on Nooksack, Bogachiel, Calawah Rivers and Olsen Creek. Hundreds of water rescues and two fatalities took place during this time period. The heavy rainfall also triggered numerous landslides due to loading on the already-saturated soils.|Much of the reported damage amounts were for both episodes in November and some of the amounts for this episode were an estimated proportion for the month.
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 12, 4:17 AM PST, 13 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
417 AM PST Fri Nov 12 2021
.SYNOPSIS...Heavy rain will continue today with an atmospheric
river remaining stretched across the region. The moisture will
shift south as a front passes through, with a brief break in the
rain expected late Friday into early Saturday. However, another
plume of deep moisture will likely bring heavy rain back into
parts of the region Sunday and Monday. Cooler, and drier,
conditions then likely follow toward the middle of next week.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...Latest radar and satellite
imagery this morning depict a deep plume of moisture aimed
squarely across the Pacific Northwest this morning. Satellite
derived precipitation water values remain in excess of 1-1.25"
with the core of the moisture band. Rainfall amounts have been
rather significant over the last 24 hours, with large swaths of
2-3 inches across portions of the coast, Olympics, and Cascades.
Given the continued influx of moisture expected through the
morning, along the satellite observations suggesting an embedded
shortwave that will provide for some focused enhancement of
precipitation rates toward the time of the morning commute. Thus,
those on the roads this morning should again remain alert for
reduced visibility and the potential for urban flooding in areas
that are low-lying and/or have poor drainage. Also cannot rule out
an isolated lightning strike in association with these stronger
convective elements, though confidence in seeing more than a few
is very low.
For a more detailed discussion of hydrologic concerns, specifically
river flooding, see the hydrology section below.
Guidance remains in fairly strong agreement that the bulk of the
moisture will begin to shift south toward mid-afternoon and
through the evening as the cold front advances southward. This
will temporarily usher in a cooler air mass, but with only a few
residual showers at that point shouldn't see much in the way of
Cascade snow save for the highest peaks. Heights rise a bit, with
a brief break in the precipitation early Saturday. This should
allow some of the rivers to recede a bit. However, the next round
of moisture is then slated to arrive Saturday evening. With the
cooler air in place, snow levels will begin relatively low but
will rise quickly again as another plume of moist subtropical air
approaches. This could lead to a quick few inches of snow at Mt.
Baker and even Stevens Pass, but with abundant moisture and
rapidly rising snow levels it shouldn't amount to much or linger
too long. Warm frontal precip likely lingers into Sunday with
ensembles suggesting a focus across the Olympics and northern
Cascades. There's still a decent spread in terms of just how much
rainfall may fall with this next atmospheric river, but given that
many rivers may still be running high, there likely will be
renewed hydrologic concerns for the basins which end up under this
heavy band. Temperatures will generally remain mild Sunday and
Sunday night in this pattern. Cullen
.LONG TERM /MONDAY THROUGH THURSDAY/...By Monday, guidance
continues to suggest the plume of deep moisture will still be over
the region but shifting south as the next cold front begins to
advance toward the region. This front will likely bring an end to
the steady rain and another rapid lowering of snow levels. With
abundant showers, expect to see a return of snow at the pass
elevations Monday night into early Tuesday. With ensembles
favoring another weak ridge toward midweek after this front, will
need to keep an eye on the potential for a few significantly
cooler nights across the region by Tuesday night and into the
midweek period with lows dipping well into the 30s and afternoon
highs only in the mid 40s across the lowlands.
&&
.AVIATION...Additional moisture associated with the atmospheric
river will impact the area in the form of moderate to heavy rain at
times through the majority of the day today. MVFR to IFR conditions
can be expected through the morning hours, with a return to MVFR/VFR
possible by the afternoon with tapering showers. Low ceilings,
moderate rain and reduced visibilities will carry through much of
the day with surface winds generally out of the SSW from 5-10 kt. A
brief break in showers is possible in the afternoon, but the next
round of heavy rain is expected to begin by Saturday morning.
KSEA...Generally MVFR at the terminal currently in between bands of
precipitation. Another round of moderate to heavy showers is moving
over the Kitsap Peninsula and should begin to impact the terminal in
the next hour or two. This will likely bring cigs down to IFR
through the mid morning hours. There is the possibility for some
brief windows of MVFR in between the heaviest showers. Surface
visibilities may be less than 3 statute miles at times, but winds
will generally be out of the SSW at 5-10 kt. Shower activity will
begin to taper off this afternoon (MVFR) for a brief break in
precipitation as the next round will arrive early Saturday morning.
Kristell
&&
.MARINE...Winds look to ease over the area waters today in the wake
of the frontal system and then look to remain calm into Saturday, as
no additional marine headlines have been issued at this time. Swell
over the coastal waters today should be between 7-10 ft, remaining
as such through the weekend. Swells look to hover in this range over
the weekend, before subsiding down to 5-8 ft on Monday. Visibilities
over the interior waters may experience some improvement this
afternoon with scattered showers as the front passes through.
Another system will move across the area waters beginning on
Saturday for another round of moderate to heavy rain, likely
yielding another round of marine area headlines.
Kristell
&&
.HYDROLOGY...Atmospheric river event in progress this evening over
Western Washington with the highest precipitation amounts from
King county southward. Rainfall amounts in the last 6 hours ending
at 9 pm/05z were in the 0.75-1.50 inch range in the Olympics,
Coast, Southwest Interior and the Cascades of Pierce and Lewis
county. Six hour rainfall amounts were lower over the remainder of
the area with 0.25 to 0.75 inches common. Rain rates will remain
in the current ranges through Friday morning before the rain
tapers off Friday afternoon. Rainfall totals by the end of Friday
afternoon expected to be in the 3 to 5 inch range over the
Olympics and the Cascades from about King county southward. Snow
level currently at least 9000 feet and will remain high through
Friday afternoon.
Flood warnings have already been issued for a number of rivers in
King, Snohomish, Pierce, and Lewis county. Additional warnings
are likely overnight into Friday morning.
After this rain event comes to an end later Friday another
atmospheric river event is possible especially for the northern
portion of the area Sunday into Monday. This will again put
Western Washington rivers under pressure with the biggest flood
threats on the rivers from King county northward.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch through Saturday afternoon for Admiralty Inlet Area-
Bellevue and Vicinity-Cascades of Pierce and Lewis Counties-
Cascades of Snohomish and King Counties-Cascades of Whatcom
and Skagit Counties-Central Coast-East Puget Sound Lowlands-
Eastern Strait of Juan de Fuca-Everett and Vicinity-Hood
Canal Area-Lower Chehalis Valley Area-North Coast-Olympics-
Seattle and Vicinity-Southwest Interior-Tacoma Area-Western
Skagit County-Western Strait of Juan De Fuca-Western
Whatcom County.
PZ...Small Craft Advisory until 4 AM PST early this morning 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-East Entrance U.S.
Waters Strait Of Juan De Fuca-Northern Inland Waters
Including The San Juan Islands.
&&
www.weather.gov/seattleThe national radar mosaic for the moment the first event began.
6 flood, 2 heavy rain. Local standard time, as filed.
Heavy rain drove a several rivers and streams above flood stage. Major flooding occurred on the Cowlitz River and moderate flooding on the Newaukum River.
Heavy rain and some snow melt caused flooding throughout much of Skagit County, especially on the Skagit and Samish Rivers. Flooding on the Skagit started on the 12th, then temporarily dropped below flood stage, before rising to major flood on the night of the 14th. 2 fatalities occurred during this time with many road, highways, and bridges closed due to water over roadway, washouts, sloughing, and debris. Town inundated including Rockport, Hamilton, Lyman, Sedro Woolley, and Mount Vernon. There was urban and small stream flooding as well on the 15th.The heavy rain also triggered a number of landslides throughout the area. Damages are reported and estimated; not all damages have been identified. Crop damages are unknown.
Heavy rain and snow melt pushed a number of rivers above flood stage. Moderate flooding occurred on the Snohomish and Skykomish Rivers, with minor flooding on the Stillaguamish. Several pulses of heavy rain from the 3 atmospheric rivers sent the rivers above flood levels multiple times during the episode. Urban and small stream flooding also occurred.
Heavy rain and some snow melt caused flooding throughout much of Clallam County, especially on the Bogachiel and Elwha Rivers. Flooding reached major severity and preliminarily a record stage. Many road, highways, and bridges closed due to water over roadway, washouts, sloughing, and debris. There was urban and small stream flooding as well on the 14th - 15th. The heavy rain also triggered a number of landslides throughout the area. Damages are reported and estimated; not all damages have been identified. Crop damages are unknown.
Heavy rain and some snow melt caused flooding that exceeded major severity on the South Fork Nooksack River and mainstem Nooksack River at North Cedarville and Ferndale. There was urban and small stream flooding as well, hitting Bellingham especially hard. The heavy rain also triggered a dozen landslides throughout the area. Significant flooding on the Nooksack River also overflowed at the City of Everson to the degree that flood waters flowed north along an old Nooksack floodway and Johnson Creek where it flooded the cities of Everson and Nooksack, WA, then combined with flooding from the Sumas River and flooded the City of Sumas, WA where over 85% of homes sustained water damage. Damages are reported and estimated; not all damages have been identified. Crop damages are unknown.
Heavy rain cause urban and small stream flooding, washing out some roads.
Heavy rain on already saturated soils caused several landslides along SR 112, including a large landslide near Sekiu that cutoff the water main to the town. One section of the highway dropped 2 1/2 feet, and other locations were buried in rock, mud, and trees.
Heavy rain on already saturated soil cause several landslide over I-5 blocking lanes, striking vehicles, and causing collisions. Road damage occurred as well. Damages estimated for vehicles and debris removal. One injury reported.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Flood, Whatcom | 2021-11-15 | 59 | Male | Vehicle/Towed Trailer | Direct |
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, November 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: 994105, 993228, 994114, 993266, 993206, 994500, 994461, 994446.