The February 13, 1979, windstorm was a natural phenomenon that took place in Pacific Canada and the United States. During the early morning, an intense

wave cyclone Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas which, along with the anticyclones of high-pressure areas, drive the weather over much of the Earth. Extratropical cyclones are capable of p ...

moved across southern

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian Provinces and territories of Canada, province of British Columbia. The island is in length, in width at its widest point, and in total area, while are o ...

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

. South of the low center, a strong atmospheric

pressure gradient In atmospheric science, the pressure gradient (typically of Earth's atmosphere, air but more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particu ...

was carried across

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

, with associated high winds. With a cold airflow moving toward the northeast interacting with the high terrain of the

Olympic Mountains The Olympic Mountains are a mountain range on the Olympic Peninsula of the Pacific Northwest of the United States. The mountains, part of the Pacific Coast Ranges, are not especially high – Mount Olympus is the highest at ; however, the easter ...

, a lee low developed east of the Olympics. The mesoscale low caused a particularly intense pressure gradient across the

Kitsap Peninsula The Kitsap Peninsula () lies west of Seattle across Puget Sound, in Washington state in the Pacific Northwest. Hood Canal separates the peninsula from the Olympic Peninsula on its west side. The peninsula, a.k.a. "Kitsap", encompasses all of Kits ...

region.

Wind velocity

At 6 mbar over 8 miles, the

geostrophic A geostrophic current is an oceanic current in which the pressure gradient force is balanced by the Coriolis effect. The direction of geostrophic flow is parallel to the isobars, with the high pressure to the right of the flow in the Northern H ...

wind potential easily exceeded 200 knots (which roughly translates to about 100 knots in ageostrophic flow over the Earth's rough surface, or 115 mph). As reported by the crew of the

Hood Canal Bridge The Hood Canal Bridge (officially William A. Bugge Bridge) is a floating bridge in the northwest United States, located in western Washington. It carries State Route 104 across Hood Canal of Puget Sound and connects the Olympic and Kitsap P ...

, average winds reached at least 80 mph out of the south, with gusts into the triple digits. These wind velocities were cross-checked on two different

anemometers In meteorology, an anemometer () is a device that measures wind speed and direction. It is a common instrument used in weather stations. The earliest known description of an anemometer was by Italian architect and author Leon Battista Alberti ( ...

at the bridge control tower.

Damage

Extensive damage to trees on surrounding private timberland also corroborate the extreme intensity of this tempest. The pressure of wind and wave on the

stressed the structure enough to cause catastrophic failure. It is suspected that a severe list in the bridge exposed pontoon access hatches to the waves, which subsequently tore the covers loose and allowed water to enter the flotation devices, causing sections to sink. It took nearly three years and over $140 million U.S. to rebuild the lost bridge.

Wind velocity

Damage

See also

Further reading