Meet Our Expert Guides

Josh has been a Yosemite Mountaineering School guide and instructor since 1993. He is a Certified AMGA Rock Guide, Certified PSIA Level III Nordic Ski Instructor, Certified in Rigging for Rescue, Wilderness First Responder, and Certified Interpretive Guide. He has more than 28 ascents of El Capitan and has completed over 70 big wall climbs including first ascent big wall expedition climbs in Greenland, Baffin Island, Antarctica, Alaska, Morocco, and Socotra Island (Yemen).

Chris is an AMGA Assistant Rock Guide, AMGA Single Pitch Instructor, Wilderness First Responder, Emergency Medical Technician, and has completed Level 1 Avalanche/Rescue courses. He started in the climbing industry in 2018 as an instructor and route setter at his local climbing gym. Prior to joining YMS, he guided climbs in other parts of the Southern Sierra and Joshua Tree. Whether you are interested in having a fun day of top roping, a class focused on techniques and systems, or are focused on pushing for the summit, Chris can't wait to help you get to the top! In his free time, Chris enjoys snowboarding, climbing new routes, and finding swimming holes.

Mark has been guiding climbing for the Yosemite Mountaineering School since 2009. He's an AMGA Certified Rock Guide, Apprentice Alpine Guide, and SPI Assistant Provider. Mark has been climbing since 1998 and has 13 El Cap ascents. He has guided in Colorado, Alaska, Mexico, and Nepal. Mark is a strong believer in "living the dream" and following your passions whatever they may be. He currently guides in El Potrero Chico in Mexico in the winter. Mark also has an EMT Certification, a Leave No Trace Trainer Certification, and a B.A. in Recreation and Environmental Studies.

Josh is a certified AMGA Rock Guide and has been a Yosemite Mountaineering School guide since 2006. His accomplishments include 30+ ascents of both El Capitan and Half Dome, and more than 100 big wall ascents. Josh has climbed both The Nose and the Salathe Wall on El Capitan together in a single day. He has solo day ascents of The Nose on El Cap in 19 hours and 30 minutes and the Regular N.W. Face of Half dome in 6 hours. He has day link ups of Half Dome and El Cap 17 hours and 20 minutes.

Garet McMackin is an AMGA Assistant Rock Guide, Single Pitch Instructor, Wilderness First Responder, and former Marine who has been living and climbing in Yosemite since 2020. He has guided extensively throughout California, the Southwest, the Pacific Northwest, and Mexico. With over a dozen big wall ascents, an expedition to Kyrgyzstan, and many years of backcountry experience, Garet brings sound judgment, strong technical skills, and a calm, safety-first mindset to every objective. When he's not guiding or climbing, Garet can be found exploring Yosemite and beyond with his partner Rachel.

Amber is an AMGA Certified Rock, AMGA Apprentice Alpine, and AMGA Apprentice Ski Guide as well as an AMGA Single Pitch Instructor. Amber has been guiding for Yosemite Mountaineering School since 2022, and has guided alpine rock and glacier mountaineering objectives in Washington's North Cascades, as well as crack climbs in the Utah desert since 2016. During the winter months she teaches avalanche education courses in Grand Teton National Park. She is also an Avalanche AIARE Course Instructor, Wilderness First Responder, and Leave No Trace Trainer.

Paul began guiding in 1996 and is an IFMGA Certified American Mountain Guide with extensive international guiding experience. As an El Capitan guide, he has many one-day ascents of El Cap to his name. He is a former Yosemite Search and Rescue team member, a Denali Lead Guide (12 summits), a Lead Guide on Rainier (10 summits in 10 attempts while guiding in 2018), and a Lead Guide on Aconcogua and Carstensz Pyramid. Paul works for the U.S. Antarctic Program as a mountaineer and Search and Rescue team member. He's a graduate of the Search and Rescue Institute of New Zealand (SARINZ) in vertical rescue training.

James is an AMGA Certified Rock Guide, Wilderness First Responder and Leave No Trace Trainer who was born and raised in Alaska. James has a great appreciation for the outdoors and has been guiding since 2011 in Alaska, Colorado, Utah, Nevada, and California. James has been guiding for the Yosemite Mountaineering School since 2018. His favorite type of climbing is long alpine rock objectives and establishing first ascent climbs. In the off season, James can be found traveling around the US guiding rock, ice climbing, and spending his personal time in the mountains. 

Jake is an AMGA Certified Rock Guide, Wilderness First Responder, and Leave No Trace Trainer. He has been guiding since 2015 and has been guiding climbing for the Yosemite Mountaineering School since 2022. He has worked in the High Sierra, Joshua Tree, Yosemite, and as far as Vietnam and China. Prior to joining YMS, Jake worked as an EMT for the Yosemite Search and Rescue team and Mammoth Mountain Ski Patrol. Jake's experience with big wall climbs in Yosemite Valley include multiple routes on El Capitan, Half Dome, Mount Watkins, Leaning Tower, and Washington Column.

Drew is an AMGA Certified Rock Guide, and Certified Single Pitch Instructor. He has been guiding for the Yosemite Mountaineering School since 2022. He has a bachelor's degree in Physics as well as a Wilderness First Responder. Prior to guiding in Yosemite, Drew was a climbing guide and instructor in Acadia National Park, Maine. He has spent a lot of time climbing long routes in the Red Rocks (Nevada), Cochise Stronghold (Arizona), Wind River Range (Wyoming), Rocky Mountain National Park (Colorado), Black Canyon of Gunnison (Colorado), El Dorado Canyon (Colorado), and Spain. Drew has climbed multiple big wall routes in Yosemite including routes on El Capitan.

Chase is an AMGA Certified Rock guide, Wilderness First Responder, and a Leave No Trace Master Educator. He's been guiding for the Yosemite Mountaineering School since 2022. He has a Bachelor of Science degree focused on Therapeutic Recreation and has worked as an adaptive climbing guide, wilderness therapy leader, and navigation and primitive skills instructor. Chase came to Yosemite in 2018 and has climbed some of Yosemite's big walls, including El Capitan.

Glen is an AMGA certified rock guide who has passed the AMGA Advanced Alpine Guide Course and Aspirant Exam. He has been guiding since 2002, and has guided and climbed extensively around the world, including in the Himalayas, Andes, Southern Alps of New Zealand, Canadian Rockies, Cascades, Rockies of the United States, Sierra Madre of Mexico, and Sierra Nevada. Significant guiding has included AmaDablam, Kyajo Ri, Kangchung Shar, and dozens of 20,000ft peaks in Nepal. In North America Glen has guided many Grade IV and V rock and alpine routes such as the Becky-Chouinard in the Bugaboos, North Face of Mt. Shuksan in the Cascades, North Ridge of Mt. Stuart in the Enchantments, and Resolution Arete in Red Rocks.

Lance grew up climbing and mountaineering in the North Cascades where he climbed and guided Mt. Rainier 26 times as well as many others. He has also climbed long, committing alpine rock and ice routes during multiple trips to Alaska, Patagonia, and Canada. As a dedicated big wall climber, Lance has climbed El Capitan more than 30 times with multiple El Cap speed records. Familiar with the Yosemite landscape, he has climbed over 200 other Yosemite rock climbs. He has a B.S. in Earth and Space Sciences and has contributed to many scientific field studies on the vertical walls of Yosemite National Park.

Mik is originally from the Pacific Northwest and is certified as an AMGA Apprentice Rock Guide, AIAIRE Avalanche Pro 1, Leave No Trace Trainer, and Wilderness First Responder. Mik enjoys sharing wilderness experiences through ski mountaineering, alpine climbing, and big wall climbing. He has climbed and skied in the Alaska Range, throughout the continental US, French Alps, Lyngen Alps, Caucasus, and Canadian Rockies. Some of Mik's favorite days in the mountains include climbing The Shield on El Capitan, The Nose in a Day, skiing the Rond and Capuchin in Chamonix, and climbing Mt. Huntington's West Face Couloir. Mik has worked on scientific research and conservation projects in the Pacific Northwest, Mojave Desert, and Antarctica. He has a BS degree in Supply Chain Logistics and a minor in Ecology.

Defne is an Apprentice Rock Guide and Certified Single Pitch Instructor. She arrived in Yosemite by way of Turkey-Maryland-New York-Colorado. She has spent the last several years guiding in Colorado's Front Range, Joshua Tree National Park, and cutting her teeth on rocks all around the country. Defne has also worked as a Climbing Steward in Yosemite National Park where she shared educational information to the public, and participated in search & rescue missions.

Char is an AMGA Assistant Rock Guide, Apprentice Alpine Guide, as well as a Certified Single Pitch Instructor. Char grew up in the ancient Blue Ridge 
Mountains of Virginia started climbing on classic east coast crags like Seneca Rocks. Before working for YMS, she split her time between guiding glaciated mountains, and alpine rock terrain in the North Cascades during summer months, then guiding rock climbs at Red Rocks, and Joshua Tree National Park in the shoulder seasons. During winter months, Char pursues ice climbing and skiing. Apart from guiding, she also works as a freelance cartographer and G.I.S. specialist.

Carlin is an AMGA Certified Rock Guide, Single Pitch Instructor, Wilderness First Responder, and Leave No Trace Trainer. After a short, successful career of competitive bouldering in New England, they pivoted to trad climbing and began guiding in 2020. Carlin joined Yosemite Mountaineering School in 2025. Some of their favorite granite climbing areas are Yosemite, Joshua Tree, and various alpine zones in the Eastern Sierra Nevada. With a background in STEM education, Carlin enjoys teaching everything from the physics of climbing equipment to the basics of rappelling.