Lost Brother Butte
Lost Brother Butte is a dormant stratovolcano located in west central Barlow County. Though geologically unrelated to the Three Sisters, the mountain's name reflects the belief of early white settlers that the peak was a distant part of the Three Sisters chain. At present, geological evidence suggests Lost Brother is more similar to the Newberry Volcano south of Bend, Oregon, though the two have separate geology and eruptive histories.
Standing at 7,929 ft (2,417 m), Lost Brother Butte is the tallest point in the county. Though its origins are in debate, evidence indicates the mountain is part of the Cascade Volcanic Arc. Its last major active phase was 5,500-4,900 years ago, though there is evidence of modest phreatic eruptions from vents on the north slope as recently as 400 years ago. At present, there is minimal tectonic or magmatic activity within the mountain, though several fumaroles on the northeast side release volcanic gases at intervals. The thermal activity associated with these fumaroles and area hot springs indicate the volcano has the potential to become active again.
While the more recent eruptions have been bimodal, consisting of basaltic lava flows and rhyolitic ash-flow tuff, the eruptive events which first formed the volcano between 600,000-580,000 years ago were primarily andesitic. A basaltic effusive eruption dated at 500,000 years ago created a long, eastward-trending ridge system on top of the existing basalt plateau formed during the Columbia River Flood Basalts event 17-14 million years earlier. The Palmer River subsequently eroded a valley through the ridge, dividing it into north and south spurs of the mountain. The town of Samuelton lies at the easternmost extent of the Palmer River Valley. The small villages of Crestview and Munro flank the western head of the valley.
Brother Drop Ski Resort can found on the southeast flank at an elevation of 4,336 ft (1,322 m).
- Memory Garden, Chapter 1