Vertical Adventures Rock Climbing School - Rock climbing instruction and guiding in Joshua Tree National Park. (Newport Beach, California) Bardini Foundation - Rock climbing, ski and mountaineering instruction and guiding, and avalanche courses. Operates in the Eastern Sierra Nevada range. (Bishop, California) Mountain Adventure Seminars - Offering rock and ice climbing and mountaineering trips throughout California and Nevada. (Bear Valley, California) Nidever Mountain Guides - Guided rock and ice climbing, ski trips, and wilderness adventures. (June Lake, California) Joshua Tree Rock Climbing School - Rock climbing instruction. Operates in Joshua Tree National Park. (Joshua Tree, California) Earthworks - Guide service based in Santa Barbara and leads trips to southern California and the southern and eastern Sierra Nevada. Shasta Mountain Guides - Guided mountaineering adventures and instruction, women's trips, rock climbing, backcountry skiing and boarding on Mount Shasta. (Mount Shasta, California) Sierra Mountain Center - Rock climbing and mountaineering instruction and guiding. Operates in the Eastern Sierra Nevada range. (Bishop, California) Sierra Wilderness Seminars - Mountaineering school offering courses and climbs in California and South America. (Mount Shasta, California)