North Sister volcano's east face (750 m, 2460 ft high) consists of ...
East face of North Sister, 750 m high. Consists of about 100 thin mafic lava flows and intercalated layers of red scoria, capped by thick summit lava flows. Remnant of Thayer Glacier feeds cirque lake. Pervasively altered yellow-orange buttress on right, 250 m thick, consists of east-dipping, palagonitized, ash-rich fragmental flow deposits.
Hildreth et al., 2013 Photograph by John Scurlock.