In the 1940s , Howel Williams completed an analysis of the Three Sisters vicinity .
In the 1940s , Howel Williams concluded that Multnomah had never existed , instead demonstrating that each volcano in the area possessed its own individual eruptive history .
In the 1940s , Howel Williams completed an analysis of the Three Sisters vicinity and concluded that Multnomah had never existed , instead demonstrating that each volcano in the area possessed its own individual eruptive history .