A deep upper trough drove an arctic airmass into southwest Washington. As multiple Pacific fronts moved over the area, a major elevation winter storm with heavy snow and freezing rain occurred over a multi-day period. This was a major, widespread, multi-faceted winter storm that caused major problems across the forecast area, even (and especially) in the lowlands.

Winter Storm in LOWER COLUMBIA, WASHINGTON
From 11-FEB-21 20:00:00 to 13-FEB-21 11:00:00 (PST-8)
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Widespread snow fell over the region beginning the night of the 11th and continued in waves through the 14th. Snow accumulations of 8 to 14 inches were fairly consistently reported across the zone. Widespread transportation delays occurred including along I-5. Scattered power outages were also reported.

Ice Storm in GREATER VANCOUVER AREA, WASHINGTON
From 14-FEB-21 16:00:00 to 15-FEB-21 03:00:00 (PST-8)
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Public

Overall, ice amounts were a little less than the Oregon side of the metro area.  Totals ranged from 0.25 to 0.75, and many thousands lost power in Clark County.
One ice-related fatality:  At 1715 PST on the 14th, one adult male, aged 57, died when he was heading southbound and lost control of his vehicle on the icy road surface, driving off the side of the Glenn Jackson Bridge near Government Island.  The vehicle and the driver's body were later found on February 17.

Winter Storm in GREATER VANCOUVER AREA, WASHINGTON
From 11-FEB-21 12:00:00 to 13-FEB-21 11:00:00 (PST-8)
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Public

A winter storm brought several rounds of heavy snow and some freezing rain to the greater Vancouver area beginning the night of the 11th continuing through the 14th. This was mostly a snow event for Clark County, with snowfall amounts ranging from around 6-10 inches downtown and East Vancouver, to up to 16 inches in northern portions of the zone. Ice accumulations up to 0.5 inch was also reported in south Vancouver. Widespread transportation delays and accidents occurred, including along I-5 and I-205. Scattered power outages were also reported. Key Impacts: transportation delays, traffic accidents, scattered power outages.

Winter Storm in SOUTH WASHINGTON CASCADES, WASHINGTON
From 11-FEB-21 16:00:00 to 13-FEB-21 11:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Given the reports of 10-20 inches of snow in the Gorge, and over two feet around Mount Hood, it seems reasonable that the South Washington Cascades would see similar totals or more.

Winter Storm in SOUTHERN WASHINGTON CASCADE FOOTHILLS, WASHINGTON
From 11-FEB-21 07:00:00 to 13-FEB-21 11:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The south Washington Cascade foothills observed heavy snowfall. A member of the public reported 11 inches in Yacolt, which is actually in far northern WAZ039 but close enough to serve as a proxy for the South Washington Cascade foothills zone.  It is likely areas closer to the Columbia Gorge received even more snow than the Yacolt report.

Winter Storm in WESTERN COLUMBIA GORGE, WASHINGTON
From 12-FEB-21 10:00:00 to 15-FEB-21 05:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Snow and wind continued after the Blizzard Warning was converted to a Winter Storm Warning.  Storm total snowfall was around 24 inches at Cascade Locks by midday the 13th, and more arrived with the next impulse on the 14th and 15th. State Highway SR 14 was closed multiple days due to the heavy snowfall.

Blizzard in WESTERN COLUMBIA GORGE, WASHINGTON
From 11-FEB-21 10:00:00 to 12-FEB-21 09:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Strong winds and heavy snow shut down I-84 east of Troutdale.  This was a transition event, from blizzard to winter storm to freezing rain.  Mark Nelsen (KPTV Chief Met) reported 15 inches of snow total, followed by 0.75 of ice.  Sustained winds of 30-45 mph with gusts 60-80 mph were reported for 12-24 hours (or more), along with heavy snow reducing visibility to near zero during the height of the wind/snow portion of the event.  I-84 finally reopened the morning of the 14th as snow decreased and changed to a brief period of freezing rain.

Winter Storm in SOUTH COAST, WASHINGTON
From 12-FEB-21 07:00:00 to 13-FEB-21 10:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Wide variation of snow and ice accumulations, with impacts mainly felt near the Columbia River.  Cathlamet reported 12 inches of snow, while Astoria and Long Beach reported very little snow.  US Hwy 101 was closed at the Megler Bridge due to falling chunks of ice from the bridge structure.  Estimated ice near Astoria ranged from 0.33 to 0.66, and similar amounts can be assumed for the other side of the river.

Winter Storm in CENTRAL COLUMBIA RIVER GORGE, WASHINGTON
From 11-FEB-21 07:00:00 to 15-FEB-21 05:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy snow fell through the central Columbia Gorge between the night of the 11th through the 14th. Trained spotters at Underwood and Willard measured 10-20 inches of snow. State Highway SR 14 was closed multiple days.

Winter Storm in SOUTHWEST INTERIOR, WASHINGTON
From 11-FEB-21 07:00:00 to 13-FEB-21 11:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The public reported 6.5 inches of snow in Ryderwood, Cowlitz County. A trained spotter report of 14.5 inches in the hills 4 miles NW of Castle Rock.  This is close enough to assume the Willapa Hills received similar totals.