Meet the Guides
Hiking Guides | Rock Climbing Guides
Hiking Guide Bios
Andrew Fischer
Andrew has been a Yosemite resident and park employee since 2014 and has been a YMS Hiking Guide since 2018. He is a seasoned backpacker, having well over a hundred nights out in Yosemite both solo and with groups, and has guided backpacking trips over a week-long for YMS. Andrew is a naturalist and loves to teach about Yosemite’s natural resources, ecology, geology, and history. He specializes in equipping people with the necessary skills to navigate the wilderness safely while leaving a minimal footprint on this beautiful National Park. Andrew has volunteered for the National Park Service Wilderness Department in the winter where he skied Yosemite’s backcountry ski trails making sure the trail blazes and signage were in-tact, issuing Wilderness Permits, and assisting with missing person searches. Andrew holds a current Wilderness First Responder since 2015, is a Leave No Trace Trainer, and is an NAI Certified Interpretive Guide.
Nick Castillo
Born and raised in Southern California, Nick grew up hiking and fishing in the Eastern Sierra every summer with his family. It was in these mountains that he developed a passion for the outdoors at a young age. After studying philosophy at California State University, Fullerton, and a brief stint in sales, Nick decided to pursue his passion for outdoor adventure instead and moved to Yosemite Valley in 2018. He loves sharing his knowledge and passion of the outdoors and Yosemite with first time visitors and hikers of all abilities. His favorite things to talk about on trail are Yosemite's history and wildlife, living in the mountains, and wilderness safety. Beside hiking and backpacking Nick also loves climbing, traveling, trail running, body surfing, diving, pizza, breakfast burritos, and a good book every now and then. Nick has trained with the Sierra Club in their Wilderness Travel Course, holds a current Wilderness First Responder, is an NAI Certified Interpretive Guide, and has been guiding with YMS since 2019.
Connor Gibson
Connor has been living, working, and exploring the Yosemite Wilderness since 2017 and has been a YMS Hiking Guide since 2021. As a former competitive swim team and climbing team coach, he loves to teach and share his knowledge and passion with others. Some things Connor likes to teach in his guided hikes are flora and fauna identification as well as skills to help you explore the outdoors in a safer way, while minimizing your footprint on beautiful Yosemite. He loves to get people off-trail and share some of the unique Yosemite backcountry. Connor has held a Wilderness First Responder certification since 2016, is a Leave No Trace Trainer, and is an NAI Certified Interpretive Guide.
Britain Andrew
Britain has been working and living in Yosemite since 2012. He has experience as an Interpretive Guide for the Yosemite Hospitality Interpretive Department where he led hikes and tours packed with information about Yosemite’s history, ecology, geology, and natural and cultural resources. He’s also worked as a Naturalist Guide for the Yosemite Conservancy where he led similar programs. He volunteered for the National Park Service Wildlife Department as a Photo Processor processing photo data from a large-scale grid of motion activated cameras tracking wildlife such as mountain lions, Pacific fishers, and Sierra Nevada red foxes. He has been a YMS Hiking Guide since 2022, holds a current Wilderness First Responder, is Leave No Trace Certified, and is an NAI Certified Interpretive Guide.
Joe Morgan
Joe Morgan has been working in outdoor recreation, education, and social services since 2010. From Akron, Ohio, Joe has worked with people in the outdoors from the mountains of North Carolina to the high deserts of Southwest Utah. After spending some time solo backpacking around Patagonia, Joe moved to Yosemite in 2015 for a season then finally settled here again in 2021 with the goal to be a hiking guide. With that dream fulfilled now, Joe is excited to share with you his knowledge of the natural and social history of Yosemite while soaking in some of the most excellent views in North America. Joe has his B.A. in Psychology, holds a current Wilderness First Responder, is Leave No Trace certified, and is an NAI Certified Interpretive Guide. He is also a volunteer facilitator for the Yosemite Wellness Coalition. In his free time Joe loves long runs on high country trails and climbing a good splitter crack.
Tammy Bergstrom
Tammy started hiking in the Los Padres National Forest and Santa Monica Mountains in Southern California over 10 years ago and has been doing it voraciously ever since. Before coming to Yosemite, she was a hiking guide for a Wellness Retreat Center in Malibu where she helped people achieve their fitness goals while finding peace and balance in nature. She loves sharing her passion of the outdoors (especially botany and wildlife) with anyone who wants to listen. In her free time, she likes to write about health topics, pan for gold, read, swim, practice photography, climb, hike, backpack, and learn new things. She has lived and worked in Yosemite since 2021 and has been a YMS hiking guide since 2022. She holds a current Wilderness First Responder, is a Leave No Trace Trainer, and is an NAI Certified Interpretive Guide.
Rock Climbing Guide Bios
Josh Helling
Josh has been a Yosemite Mountaineering School climbing guide since 1993. He is a Certified AMGA Rock Guide, Certified PSIA Nordic Ski Instructor, Certified in Rigging for Rescue, and a Wilderness First Responder. He has more than 27 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). Josh has many alpine ascents and ice climbs as well. He has been a member of Yosemite Search and Rescue and is a professional rigger, photographer, and videographer specializing in natural history and high angle camera rigging. He’ s also a Leave No Trace Trainer.
Nathan Kerr
Nathan has been a Yosemite Mountaineering School climbing guide since 2007. He is an AMGA Certified Rock Guide and has completed the AMGA Alpine Guide and AMGA Ski Guide Courses. Nathan is a former Pacific Crest Outward Bound School Instructor, avid rock climber, backcountry skier, and alpine climber on three continents. He loves pursuing adventure and sharing outdoor education with others. He has also been a Yosemite Cross-Country ski guide and holds an American Avalanche Institute Certification Level I & II. Nathan is a Wilderness First Responder and Leave No Trace Trainer.
Mark Grundon
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.
Miranda Oakley
Miranda has been living, working, and climbing in Yosemite National Park since 2006 and is an AMGA Certified Rock Guide. She is a big wall climber and has worked as a guide for an international outdoor recreation company based in China. She has traveled and climbed extensively throughout the United States, Asia, Spain, South and Central America. She earned a B.A. in International Studies with a focus in Latin America and the Spanish Language. Miranda loves the backcountry of the Sierra Nevada and shares her knowledge and enthusiasm for the outdoors with her clients. Miranda is a Wilderness First Responder and a Leave No Trace Trainer.
Josh McClure
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. Josh has extensive alpine experience including ascents of Aconcagua, Fitz Roy, first ascent big wall free climbs, and first solo link ups in Patagonia’s Fitz Roy range. Josh has also climbed and trekked in many of the world’s mountain ranges including the Himalayas, the Andes, the Atlas, the Pyrenees, the Sierra, and the Rockies. His certifications include a B.S. in Natural Resources Management, Certified Interpretive Guide through National Association of Interpretation, is a Wilderness First Responder, and a Leave No Trace Trainer.
Nick Malik
Nick has been guiding since 2012 across North America and for the Yosemite Mountaineering School since 2019. He is an AMGA Certified Rock and Ski Guide, Leave No Trace Master Educator, AMGA Apprentice Alpine Guide, Avalanche Level 3 Certified, and a Wilderness First Responder. Nick spends winters ski guiding in Jackson Hole and climbs in the desert during his time off. He has climbed over 600 days in Indian Creek including the establishment of many new routes. His climbing resume includes numerous free ascents of 5.13 cracks, onsighting up to 5.12+ trad, and many one-day ascents of El Capitan. He has a BS in Cellular and Molecular Biology.
Amber Smith
Amber has been guiding for the Yosemite Mountaineering School since 2022. Since 2016 she has guided alpine rock and glacier mountaineering objectives in Washington’s North Cascades, as well as crack climbs in the Utah desert. During the winter months she teaches avalanche education courses in Grand Teton National Park. Amber is an AMGA Apprentice Rock, Alpine, and Ski Guide as well as a Single Pitch Instructor. She is also an Avalanche AIARE Course Instructor, Wilderness First Responder, and Leave No Trace Trainer. Amber graduated with a degree in Geographic Information Systems (GIS) and wrote her undergraduate thesis on what she calls “Feminist Outdoor Leadership: A guide to facilitation strategies for inclusion and participant empowerment in outdoor adventure.” She looks forward to exploring the mountains with you!
Paul Koubek
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. Has guided and climbed in Alaska, India, Patagonia, Thailand, Mexico, New Zealand, Canada, and Antarctica with significant Antarctic traverse experience (4000+ miles). Paul currently serves as an elected member of the Board of Directors for the American Mountain Guide's Association. He holds Wilderness First Responder and Leave No Trace Trainer Certifications, as well as being an AMGA certified Rock, Alpine, and Ski guide.
Greg Coit
Greg is a Wilderness First Responder, Leave No Trace Master Educator, and is an AMGA Certified Rock Guide. He has worked as a Yosemite Mountaineering School guide since 2011 with multiple guided ascents of El Capitan, Half Dome, Sentinel Rock, and other big walls throughout Yosemite. Greg spends his free time backpacking, skiing, and rock climbing. Greg also enjoys climbing alpine peaks in the Sierra Nevada Mountain Range. He has a bachelor’s degree in Outdoor Education from the University of New Hampshire, is a graduate from the National Outdoor Leadership School, and has guided rock climbing and backpacking in New England, North Carolina, Washington, and Yosemite. He holds a Leave No Trace Trainer Certification.
James Gustafson
Having been born and raised in Alaska, James has a great appreciation for the outdoors. He has been guiding since 2011 in Alaska, Colorado, Utah, Nevada, and California and has been guiding for the Yosemite Mountaineering School since 2018. His favorite type of climbing is long alpine rock objectives. In the off season he can be found traveling around the US guiding rock and ice climbing, and spending his personal time in the mountains. James is an AMGA Assistant Rock Guide, Wilderness First Responder and Leave No Trace Trainer.
Camden Clements
Camden has been rock climbing since 2001 and has been a YMS guide since 2017. He is originally from South Carolina and quit his job as a software developer in 2014 to hit the road and enjoy rock climbing around the US as well as the world. Camden enjoys climbing on Yosemite's big walls like El
Capitan, but also enjoys other types of climbing like sport climbing, bouldering, and mountaineering. He has climbed both the Salathe Wall and The Nose on El Capitan together in a single day. He has also climbed Half Dome and El Capitan in the same day. Camden is technically gifted with vast amounts of Yosemite climbing experience. He is soft spoken, patient, and enjoys helping others realize and achieve their climbing goals. Camden is a member of Yosemite Search and Rescue and has at least one speed record on El Capitan. He is a Wilderness First Responder and Leave No Trace Trainer.
Jake Squire
Jake 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 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. He has also climbed many free routes on the granite domes of Tuolumne Meadows. Sport and trad climbing route accomplishments extend into the 5.13 range. Jake loves teaching and sharing his passion for rock climbing with his clients. He is a Wilderness EMT, Leave No Trace Trainer, and has passed the AMGA Advanced Rock Guide Course.
Benton Mitchell
Benton is a Certified AMGA Rock Guide and Wilderness First Responder with a degree in Adventure Education. He has been guiding for the Yosemite Mountaineering School since 2022. Originally from Pennsylvania, Benton has been climbing since 2015 and has climbed all over the country as well as in Israel. He has hiked the Appalachian Trail as well as the Pacific Crest trail and has guided in areas including Zion National Park, Yosemite National Park, and the surrounding Sierra Nevada Mountain Range. His climbing resume includes El Capitan routes and other big walls, as well as many free climbing routes. His passion is finding the balance between adventure and challenge, and mentoring people with climbing by sharing the joy that it can bring.
Drew Megura
Drew is an AMGA Apprentice 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), and El Dorado Canyon (Colorado). Drew has climbed multiple big wall routes in Yosemite including routes on El Capitan. Drew is a welcoming and patient guide that enjoys sharing safety information with Yosemite National Park visitors.
Chase Colley
Chase is an AMGA Apprentice 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. He enjoys moving over stone on long classic free climbs in Yosemite Valley, Tuolumne Meadows, and the High Sierra. During the winters Chase can be found climbing adventure routes in the San Juans of Colorado and desert towers in Southwest Utah.
