43° F

Experience Level



10-12 miles/day


8,600-11,000 feet

Registration Fee


Program Overview: Join naturalist guides and fellow adventurers for a Yosemite Field School backpacking trip to Mt. Lyell, the highest point in the park (13,114′). On a challenging three-day trek, you’ll dig into alpine ecology and geology, learn how shifting conditions are affecting snow and ice in the Sierra Nevada, and see firsthand what remains of the now-stagnant ice body on the slopes of Mt. Lyell that, until recently, was Yosemite’s largest glacier.

This is a strenuous backpacking trip. We’ll cover about 30 miles over the course of three days, at high elevations, with some off-trail travel on steep, rugged terrain.

The trip kicks off with a Thursday evening get-together at Tuolumne Meadows Campground, where you’ll meet your guide and fellow adventurers, and review the route, Leave No Trace ethics, and safety tips, including our COVID-19 procedures (see below).

On Friday, your three-day journey to and from Mt. Lyell begins. As you backpack to and from the southeast end of the Cathedral Range, your guides will lead you on an exploration of the past, present and future of Yosemite’s high country. You’ll have the chance to learn about the area’s icy history; see a variety of glacial features, such as moraines, cirques, polish, striations, erratics and chatter marks; observe an alpine habitat up close; and consider how human-driven climate change is shaping the future of ecosystems, from Yosemite’s high peaks to far beyond the park boundary.

By the time you hike back out to the trailhead on Sunday afternoon, you’ll have a deep appreciation of the High Sierra, home to hardy plants and animals, strong winds, beaming sunlight, sporadic mountain storms — and visibly vulnerable to the effects of climate change.

For a preview of Yosemite’s glacial story, read about recent donor-funded glacier research, and watch the “Glaciers” episode of Yosemite Nature Notes.

Know Before You Go

  • When: Thursday, July 29 (orientation at 7:30 pm) to Sunday, August 1. Depart for backpacking trip on July 30 at 8 am, return August 1 at around 5 pm.
  • Where: Tuolumne Meadows Campground (orientation) and Mt. Lyell area (backpack).
  • Registration includes: Guided backpacking trip, park entry (as needed), bear-proof canister rental, Yosemite Wilderness permit, and two nights of tent camping at a shared group site at Tuolumne Meadows Campground before and after the trip (July 29 and August 1). There is no discount if you choose not to use the included gate pass or campsite.
  • Lodging options: Tent camping included. Camping dates cannot be adjusted. No additional lodging options have been arranged for this program, but guests are welcomed to find their own alternate accommodations if desired.
  • Experience level: Participants must have prior backpacking experience at elevations above 10,000 feet, be very physically fit, and be ready to carry personal gear for 30 miles of high-elevation hiking over three days, including some off-trail travel on steep, rugged terrain. We recommend spending a few days and nights at high elevation immediately before the trip, to adjust to the altitude.

View a suggested packing list.

COVID-19: We have implemented special safety measures to keep participants and instructors safe during the ongoing pandemic. For example, participants will hike single-file and keep moving to avoid crowding the trail, and instructors will stop to offer interpretation only when there is ample space to stay at least six feet apart. Please review our COVID-19 procedures for details.