Flooding in Washington, January 2 to 11, 2021

Name: Flooding in Washington, January 2 to 11, 2021
Start: 2021-01-02T00:00
End: 2021-01-11T04:45
Location: Washington

January 2 to 11, 2021 · NWS SEW · 5 events in 5 counties and zones

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $1.7 million
Crop damage: None recorded
Events: 5

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.

What happened

The episode as NWS SEW wrote it up.

From December 29 - January 16, a strong and persistent Aleutian Low pressure system developed in the eastern Pacific which directed the jet stream and primary storm track at Washington State that resulted in a rapid series of atmospheric rivers and wind storms that battered Washington State. Water vapor transport into Washington State averaged 160-200% of normal during the period from December 29 through January 16. Numerous periods of heavy rain occurred during the episode, which in turn resulted in widespread and sustained river flooding, urban and small stream flooding, mudslides, and landslides in addition to the significant and widespread impacts from high winds, pounding surf, and coastal flooding.

During the wettest portion of this 19-day period, Washington State experienced widespread precipitation totals between 200% and 350% of normal. The prolonged bouts of moderate to heavy rain between December 29, 2020 and January 7, 2021, resulted in 8 major rivers exceeding flood stage; with 4 of them exceeding moderate flood.

What forecasters said that day

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 Jan 1, 7:40 PM PST, 4 hours 20 minutes earlier.

Area forecast discussion, Jan 1, 7:40 PM PST, 4 hours 20 minutes before

Area Forecast Discussion
National Weather Service Seattle WA
740 PM PST Fri Jan 1 2021

.SYNOPSIS...A front moved through Western Washington this evening.
A strong frontal system will arrive Saturday and move inland late
Saturday night. Another weather system will arrive Monday and yet
another front will arrive around the middle of next week.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...A front moved through
Western Washington earlier this evening. The wind advisory ended at
7pm and the weather will settle down briefly overnight before the
next strong front arrives.

Saturday will bring more rain, wind, and high surf. Several inches
of rain are likely to fall in the mountains, with the heavier rain
in the afternoon and evening--and mainly in the evening for the
lowlands. Rivers will rise and a flood Watch is in effect. Winds
will be strongest along the coast where gusts to 60 mph are
possible. Interior winds will be blustery too, especially in the
north interior and near the sound with gusts to 45-50 mph. High surf
will reach the beaches and that advisory is from 10 AM Saturday to 4
PM Sunday.

On Sunday we'll see a short break in the action although rivers
will still be running high and seas still around 15-20 ft. Then more
wet weather will return Sunday night and Monday with yet another
weather system. 19

.LONG TERM /TUESDAY THROUGH FRIDAY/...Long wave troughing over the
West will keep the weather pattern active through the long term
period. Expect more rain and mountain snow through the upcoming
week with very little breaks in between systems. Temperatures
throughout will trend close to seasonal normals. 33

&&

.AVIATION...MVFR cigs through tonight with VFR possible at times
late tonight into Saturday. Another round of rain, heavy at times,
Saturday for lowered visibilities. Southerly winds 8 to 14 knots
tonight with gusts to 25 knots. Stronger southerly winds on Saturday
with gusts 30-35 knots possible, mainly along the coast and northern
areas.

KSEA...MVFR cigs through most of the evening and overnight hours.
MVFR cigs tonight likely to persist into Saturday morning with rain
continuing throughout the day. Rain may be heavy at times and reduce
visibilities at the terminal. South winds 8 to 14 knots, increasing
into Saturday with gusts between 25 to 30 knots possible.

Kristell

&&

.MARINE...Active weather through much of next week as a series of
strong frontal systems move through the area. Small Craft Advisory
winds for the waters tonight. A stronger front will move through on
Saturday with gales for most waters. High end gales expected for the
coastal waters, especially late afternoon and evening along the
southern tier of the area. Seas rising to 20 to 25 feet with this
system and continuing to remain 15 to 20 feet through Monday.

Severe bar conditions at Grays Harbor Bar continuing for most of the
next week.

Confidence remains high that a very active period with additional
periods of gale force winds (or higher) affecting a large swath of
the area waters into much of next week with the continuation of
rough coastal waters of 15 to 20 feet.

Kristell/JD

.HYDROLOGY...Flooding continues on the Skokomish River in Mason
County today. Elsewhere, widespread minor to moderate river flooding
is possible this weekend weekend, as another round of heavy rain
will move across the region. Total rain amounts of 1 to 3 inches for
the lowlands and 4 to 8 inches in the mountains are expected through
the weekend. Snow levels will rise to around 6000 feet, lowering
closer to 4,000 feet at times, which may be a limiting factor in
rises on some area rivers.

In addition, high rainfall rates Saturday afternoon and evening
could also lead to localized urban and small stream flooding issues.
Soil moisture is also high, so this additional rain could cause some
landslides.   Cullen

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch from Saturday morning through late Sunday night for
     Admiralty Inlet Area-Bellevue and Vicinity-Bremerton 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-San Juan
     County-Seattle and Vicinity-Southwest Interior-Tacoma Area-
     Western Skagit County-Western Strait of Juan De Fuca-
     Western Whatcom County.

     High Wind Watch from Saturday morning through Saturday evening
     for Central Coast-North Coast.

PZ...Small Craft Advisory until 4 AM PST Sunday for Grays Harbor Bar.

     Storm Watch from Saturday morning through late Saturday night
     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 7 AM PST Saturday
     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.

     Gale Warning until 6 PM PST this evening 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.

     Gale Watch from Saturday morning through Saturday evening for
     Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De
     Fuca.

     Small Craft Advisory until 10 AM PST Saturday for East Entrance
     U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters
     Including The San Juan Islands.

     Gale Warning until 4 PM PST this afternoon for East Entrance
     U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters
     Including The San Juan Islands.

     Gale Watch from Saturday morning through late Saturday night for
     Northern Inland Waters Including The San Juan Islands-Puget
     Sound and Hood Canal.

     Gale Watch from 2 AM PST Saturday through Saturday afternoon for
     West Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 2 AM PST Saturday for West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Gale Watch from Saturday afternoon through late Saturday night
     for Central U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 4 PM PST this afternoon for Central
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 10 AM PST Saturday for Admiralty
     Inlet.

     Gale Warning until 3 PM PST this afternoon for Admiralty Inlet.

     Small Craft Advisory until 10 AM PST Saturday for Puget Sound
     and Hood Canal.

&&

www.weather.gov/seattle

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

5 flood. Local standard time, as filed.

Flood, Mason

When: January 2, 12:00 AM PST to January 7, 5:30 PM PST
Where: Mason County, 6.56 mi WNW of Skokomish River Near Potlatch to 1.62 mi W of Skokomish River Near Potlatch
Cause: Heavy Rain
Property damage: $8,000
Reported by: River/Stream Gage
Coordinates: 47.353, -123.305

The Skokomish River went above flood stage December 31st, 2020 and stayed above flood stage until January 7, closing roads and cutting off access to the valley. I was above moderate flood at times everyday from January 2nd and the 6th. Urban and small stream flooding occurred as well.

Flood, Clallam

When: January 2, 6:30 PM PST to January 3, 1:00 AM PST
Where: Clallam County, 4.3 mi S of Quillayute to 2.42 mi SSW of Forks Arpt
Cause: Heavy Rain
Property damage: $121,000
Reported by: River/Stream Gage
Coordinates: 47.888, -124.527

The Bogachiel River was above flood stage Jan 3 to 4, 2021.

Flood, Grays Harbor

When: January 2, 10:00 PM PST to January 11, 4:45 AM PST
Where: Grays Harbor County, 5.52 mi NNW of Satsop to 5.2 mi SW of Brady
Cause: Heavy Rain
Property damage: $60,000
Reported by: River/Stream Gage
Coordinates: 47.071, -123.534

The Satsop River hit flood stage on the 2nd and Moderate flood stage on the 3rd. Flooding on the Chehalis River at Porter started on the 5th, cresting above Moderate flood before falling below flood on the 11th. Urban and small stream flooding occurred as well.

Flood, Lewis

When: January 3, 12:15 AM PST to 7:00 PM PST
Where: Lewis County, 2.91 mi NW of Doty to 2.04 mi S of Pe Ell
Cause: Heavy Rain
Property damage: $1.4 million
Reported by: River/Stream Gage
Coordinates: 46.663, -123.309

The Chehalis River near Doty, Newaukum River near Centralia rose above flood stage Jan 3. Urban and small stream flooding occurred as well.

Flood, Thurston

When: January 3, 6:00 AM PST to January 4, 8:30 AM PST
Where: Thurston County, 2.76 mi WSW of Plumb to 2.53 mi SE of Bucoda
Cause: Heavy Rain
Property damage: $63,000
Reported by: River/Stream Gage
Coordinates: 46.828, -122.899

The Skookumchuck River near Bucoda and Chehalis River near Grand Mound exceeded moderate flood stage. Urban and small stream flooding occurred as well.

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Washington in 2021 Every state in 2021 This day in weather history Warnings in Washington, January 2021

Sources

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: 993931, 993953, 993933, 993951, 993946.