Ask people to name the deepest canyon in the United States, and you might hear the Grand Canyon being given in answer. But it is not. There is another which is over 2,000 feet deeper. It has the off-putting name of Hells Canyon. It is located close to the borders of Oregon, Idaho and Washington states. It is 10 miles wide and 1.5 miles deep. It was carved out by the Snake River.
Geologists believe that recent research shows that its creation was quick as related to geological time. It is believed that around 2 million years ago, there was a very large flood in that area which created the river and then the gorge. Understanding the history of canyons is difficult, because as the river cuts deeper and deeper into the ground, it literally washes away the important evidence of the time. But geologists have estimated that Hells Canyon was created quickly because it is so steep. A much slower process would result in a gorge with less steep sides.
However, the research team investigating the canyon found caves along the gorge. When they entered, they discovered sediment dating back to when each of the caves were formed and the river left its evidence as it carved deeper. There are also changes in the steepness of the canyon. These are called “knickpoints”, and indicate where a river might have intersected it in the past.
All of this new research has helped geologists to understand part of the history of Hells Canyon. They think it began forming around 5 million years ago when water from Lake Idaho was somehow diverted to form the Snake River. Then, as we said, around 2 million years ago, the process of carving out Hells Canyon, sped up. Both the Grand Canyon and Hells Canyon have similarities like their size and length, but the Grand Canyon is thought to have been formed around 5 million years ago.
So, if you are ever in the area, take a trip to Hell. It might be deeper than you think.
