All streams naturally returned to within their banks by November 11. In addition for smaller streams, urban and small stream flood advisories and areal flood warnings were issued by both NWS Seattle and Portland forecast offices. In all, 15 western Washington rivers reached all-time record flood crest levels. NWS Seattle (41), NWS Portland (6), NWS Spokane (1) and NWS Pendleton (4) issued flood warnings for 52 flood warning points throughout the state during the event. The heavy rainfall amounts led to widespread flooding involving nearly all western Washington rivers and four rivers east of the Cascades. During the overall event, June Lake received 38.20 inches, Swift Creek 36.40 inches and Sheep Canyon 28.00 inches. Additionally, June Lake and Swift Creek near Mt St Helens had 24-hour precipitation totals of 15.20 inches and 14.60 inches respectively on Nov 7th. They included SeaTac Airport with 3.29 inches (old record 0.99 inches in 1990), Olympia with 4.31 inches (old record 1.74 inches in 1980) and Quillayute Airport near Forks with 2.38 inches (old record 1.92 inches in 1999). In addition, several other locations broke daily rainfall records. Stampede Pass in the central Washington Cascades received an all-time daily record rain total of 8.22 inches on Nov 6, breaking the old record of 7.29 inches set on Nov 19, 1962. The mountains had little if any snow pack, so the floods were driven solely by the heavy rainfall amounts. This storm, fueled in part from sub-tropical moisture associated with former western Pacific Typhoon Cimaron, produced rain amounts of between 10 to 38 inches in the Cascades and Olympics and 4 to 10 inches in western Washington lowlands during this period. A strong, warm and wet Pacific weather system brought copious amounts of rainfall to Washington from November 2 to 7, with subsequent major flooding that extended through November 11. November 2006 was the wettest November on record, mostly from a single event. This flood resulted in the highest flood of record on many southwest Washington rivers, most notably the Chehalis, Skookumchuck, and Nisqually. The affected rivers were the Cedar, Chehalis, Columbia, Cowlitz, Klickitat, Naches, Nisqually, Palouse, Skokomish, Skookumchuck, Snoqualmie, Walla Walla, Yakima Rivers 13 rivers and a creek saw record floods. The affected counties were Adams, Asotin, Benton, Clark, Columbia, Cowlitz, Garfield, Grays Harbor, King, Kitsap, Kittitas, Klickitat, Lewis, Lincoln, Pierce, Skagit, Skamania, Snohomish, Spokane, Thurston, Wahkiakum, Walla Walla, Whitman and Yakima. More than 2,600 homes were flooded, dozens of bridges were lost, an estimated $120 million in damages, and 3 fatalities occurred in Washington. The heavy rain and rapid snowmelt combined to produce record and near-record flooding, mudslides, and avalanches. In addition to record precipitation in some of the mountainous areas, melting snowpack across the region contributed as much as half of the total runoff in some locations. During the week of February 4-10, warm air and excessive precipitation, typical Atmospheric River conditions, and the resultant snow melt caused widespread flooding that continued into the following week. Furthermore, the ground was frozen or saturated so subsequent rainfall was directed mostly into runoff. A precursor to the event was an extended period of cold temperatures that brought snow to low elevations and created river ice on the east side of the Cascades. The February 1996 flood was one of the most widespread across the whole Pacific Northwest and Washington: 24 of 39 Washington State counties were affected. This flood wiped away Fort Cascade and the town of Cascade, WA, which was never rebuilt.
There was a bigger flood on the Columbia River in June of 1894, the record crest of the Columbia reached 1.24 million cgs at the Dalles and 34.4 ft. The flow at the Dalles river gage crested at 1 million cubic feet per second (cfs). The flow at the Methow River, which surpassed its flood stage level of 10 feet, and rose to 12.30. This flood event spurred a move to build more dams and renewed a focus on flood control.Īt the Vancouver river gauge, the Columbia crested on June 13-14 at 31.0 feet above sea level. Much of the business district of Kennewick was underwater and one death was reported there. In Washington, flooding occurred in Vancouver, Kalama, Woodland, Longview, Kennewick, and Richland. Elsewhere in the Columbia Basin, the flood destroyed 5,000 homes, forced some 50,000 people to evacuate and caused an estimated $100 million in damage.
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