Let’s remember when the Hood Canal Bridge sank, on this day in 1979 (February 13)

As KOMO’s Scott Sistek tells it:

Feb. 13, 1979 was the great “Hood Canal Bridge Storm” — so named because winds reaching hurricane force strength tore apart critical parts of the floating bridge, causing part of the bridge to sink.

According to noted local windstorm researcher Wolf Read, the storm was estimated to have a central pressure of about 968 mb (28.58") when it passed a buoy 315 miles west of Aberdeen, then followed a classic track, moving along the Washington coast, making landfall in southern Vancouver Island.

The peak of the storm hit that morning with the greatest wind speeds in a narrow area between Tacoma and Bellingham. Olympia’s peak gust was just 44 mph, but Tacoma hit 53, Sea-Tac hit 60 and Bellingham hit 75.

But it was even worse along the northern edge of Kitsap County and the Hood Canal area, where southwest gusts reached over 80 mph, and some estimates are speeds hit up to 120 mph! Read calls it “one of the greatest storms to strike the upper Kitsap region.” Making it worse, the winds were perfectly aligned with the Hood Canal, turning it into wind tunnel, aligned perpendicular to the bridge span.

HistoryLink gives some more context:

The bridge is one-and-one-fifth miles long (7,869 feet). It has approach spans and truss spans built on piers, and a center span built on 23 floating hollow concrete pontoons, each composed of 93 cells, and each weighing about 5,000 tons. These were bolted together to form two continuous rigid piers. At the center is a retractable pontoon draw span that opens to a 600-foot clearance. The floating portion was held in place by braided steel cable tied to 42 concrete-block anchors each weighing more than 500 tons.

Pontoon bridges were designed for calm lakes. Hood Canal is not a man-made canal but a fjord — an arm of the sea — 55 miles long and subject to heavy currents, tides, and giant waves. The water level rises and falls as much as 18 feet. Even before the bridge opened on August 12, 1961, there were engineering worries and technical problems. Storms tended to damage the bolted joints that hitched the pontoons together.