Sky Watch Friday Rain over the Columbia River
Columbia River
Vista House on the view point to the right
Click on the photograph for better viewing and
click on the links to learn more about this region and some of its history
This is one of my favorite spots in the Pacific Northwest. I can just imagine Lewis and Clark viewing the mighty Columbia River.
The expedition of Meriwether Lewis and William Clark is one of my favorite historical subjects.
The Columbia River (known as Wimahl or Big River to the Chinook-speaking natives who live on its lowermost reaches) is the largest river in the Pacific Northwest region of North America. It is named after the Columbia Rediviva, the first ship from the western world known to have traveled up the river. It stretches from the Canadian province of British Columbia through the U.S. state of Washington, forming much of the border between Washington and Oregon before emptying into the Pacific Ocean. The river is 1,243 miles (2,000 km) long, and its drainage basin is 258,000 square miles (670,000 km²).
Measured by the volume of its flow, the Columbia is the largest river flowing into the Pacific from North America and is the fourth-largest river in the United States. The river's heavy flow, and its large elevation drop over a relatively short distance, gives it tremendous potential for the generation of electricity. It is the largest hydroelectric power producing river in North America with fourteen hydroelectric dams in the United States and Canada.
The Columbia and its tributaries are home to numerous anadromous fish, which migrate between small fresh water tributaries of the river and the Pacific Ocean. These fish—especially the various species of salmon—have been a vital part of the river's ecology and the local economy for thousands of years.
Volcanic activity in the region has been traced to 40 million years ago, in the Eocene era, forming much of the landscape traversed by the Columbia. In the Pleistocene era (the last ice age, two million to 700,000 years ago), the river broke through the Cascade Range, forming the Columbia River Gorge.
The river and its drainage basin experienced some of the world’s greatest known floods toward the end of the last ice age. The periodic rupturing of ice dams at Glacial Lake Missoula resulted in discharge rates ten times the combined flow of all the rivers of the world. This happened as many as forty times over a thousand-year period.
Water levels during the Missoula Floods have been estimated at 1,250 feet (380 m) at the Wallula Gap, 830 feet (250 m) at Bonneville Dam, and 400 feet (120 m) over modern Portland, Oregon. The floods' periodic inundation of the lower Columbia River Plateau deposited rich lake sediments, establishing the fertility that supports extensive agriculture in the modern era. They also formed many unusual geological features, such as the channeled scablands of eastern Washington.
A mountain on the north side of the Columbia River Gorge, likely a result of the Cascadia earthquake in 1700, in an event known as the Bonneville Slide. The resulting land bridge blocked the river until rising waters tunneled through and finally washed away the sediment. In 1980, the eruption of Mount St. Helens deposited large amounts of sediment in the lower Columbia, temporarily reducing the depth of the shipping channel by 25 feet (7.6 m)
I hope you have enjoyed this piece of history and geology of the area.
To participate in Sky Watch Friday visit Wiggers World.
Troy and Martha
Vista House on the view point to the right
