The North Sister is seen to the left and the South Sister to the right.

[Northern ice-fields of Three Sisters, seen from crater of North Sister. Peak of Middle Sister in distance.]

This image is included in Building Oregon: Architecture of Oregon and the Pacific Northwest, a digital collection which provides documentation about the architectural heritage of the Pacific Northwest.

This image is included in Building Oregon: Architecture of Oregon and the Pacific Northwest, a digital collection which provides documentation about the architectural heritage of the Pacific Northwest.

The North Sister lies to our left and the Middle Sister is in the right background and the high peak this side of Middle Sister is half way up the slope.

Geologists believe that the Three Sisters region was originally covered by one great mountain which they call Mount Multnomah. The top and center of this mountain was blown off by a terrific explosion leaving...

[Mountain stream in Three Sisters Wilderness. Peak of Middle Sister in background.]

[Ice fields and crevasses on Three Sisters glacier.]

[Three climbers on large piece of ice on glacier, Three Sisters area. Crevasse and ice fall in foreground.]

[Crevasse in glacier in Three Sisters Wilderness.]