By Elaine Beck-Bruns Jeff Renner is a popular television weatherman and sailboat enthusiast in the Pacific Northwest. He begins with a brief synopsis of the northwest geology and history. The Pacific Northwest mountains were caused by geological forces acting beneath the earth's surface.
Ocean floors are a collection of plates.
The plates float on partially melted rock in the upper region of the earth's interior called the mantle. The Pacific Northwest plate is centered far out in the Pacific Ocean. Over the last 100 million years, collision forces have pushed up mountain ranges, including the Cascades. A large trough runs alongside the west side of the ranges beginning in Oregon, continuing into the Puget Sound basin in Washington and into the Strait of Georgia in British Columbia, Canada. Easterly, land rises to form the Cascade Range, which extends from northern California through Oregon and Washington merging into the British Columbia Coast Mountains.