DescriptionSouth Sister lava flows, USGS.jpg English: "Aerial view of the south flank of South Sister composite volcano showing numerous blocky lava flows erupted...
144 1984 1488 Rock Mesa obsidian flow 1379 243 213 179 1984 1488 South Sister 402 424 114 82 1984 1488 Middle Sister English applies to jurisdiction:...
a group of lava flows on the flank that were extruded about 2000 years ago. " Date 1995 Source http://vulcan.wr.usgs.gov/Volcanoes/Sisters/Images/framework...
South Sister, Middle Sister, and North Sister. In the left foreground is the 'Newberry' flow of rhyolite lava, which is 2200 years old, one of the most...
