How Mount Mazama Became a Lake

Crater Lake wasn’t always a lake. Knute Berger tells the story of when a blast 50 times the size of Mt St. Helens' blanketed the PNW in ash.

Crater Lake National Park in southern Oregon is known for its crown jewel: a brilliantly blue and very deep alpine lake. But some 8,000 years ago, this lake was a mountain. 

Then the mountain erupted, blowing its top and layering ash so far afield that it impacted wildlife in Canada. Indigenous people carry oral traditions that share what it was like to witness the blast. 

Crosscut’s resident historian Knute Berger unearthed this history in a recent episode of the Mossback’s Northwest video series, but there is more left to uncover. 

In this episode of Mossback, Berger joins co-host Stephen Hegg to more deeply understand the geologic history of the blast and the cultural history of what eventually became known as Mount Mazama. They also discuss the chance of this or any other volcano in the Pacific Northwest blowing again — and what impact that could have on all of us. 

For more on all things Mossback, visit crosscut.com/mossback. To reach Knute Berger directly, drop him a line at knute.berger@crosscut.com. And if you’d like an exclusive weekly newsletter from Knute, where he offers greater insight into his latest historical discoveries, become a Crosscut member today.

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Credits

Hosts: Stephen Hegg, Knute Berger

Producer: Seth Halleran

Story editors: Sara Bernard and Sarah Menzies