Keywords: wilderness donated by donald graham donatedbydonaldgraham environmental forest forest service forestservice geological geology lake middle sister middlesister mountains north sister northsister oregon recreation ridge scenic sky snow south sister. hills southsisterhills stream tam macarthur ridge tammacarthurridge three sisters mountains threesistersmountains three sisters wilderness threesisterswilderness us forest service usforestservice watershed united states of america unitedstatesofamerica deschutes deschutes nf deschutesnf deschutes national forest deschutesnationalforest oregon's cascades oregonscascades eastern oregon easternoregon national forest nationalforest national forests nationalforests willamette willamette nf willamettenf willamette national forest willamettenationalforest pacific northwest pacificnorthwest landscape mountain peak mountain outdoor piste mountainside mountain ridge arete hill sport Three Sisters from Tam Macarthur Ridge in the Three Sisters Wilderness on the Deschutes National Forest in Oregon's Cascades, Donated by Donald Graham Three Sisters from Tam Macarthur Ridge in the Three Sisters Wilderness on the Deschutes National Forest in Oregon's Cascades, Donated by Donald Graham |