Hiking and Mountaineering

IMR groups hiking, peak bagging and mountaineering trips together. We use several criteria in our trip descriptions to classify our various types of trips, focusing on round-trip mileage and total elevation gain. No classification system is perfect, and trip difficulties can vary greatly depending on the season and other factors. If after reading the trip description you have any questions about a trip's difficulty, contact the trip leader.


Hiking trips (including some trips that require rock-climbing skills) are normally classified as A through D, with “A” being the easiest and “D” being most difficult.

Hiking and Mountaineering Trip Classifications

  • Class A: Up to 8 miles round trip and 1200 ft. elevation gain. Prior hiking experience is usually not necessary; some level of physical fitness is helpful.
  • Class B: Up to 8-12 miles round trip and/or up to 2500 ft. elevation gain. Moderate to strenuous physical activity. Some prior experience is beneficial.
  • Class C: Up to 15 miles round trip and 3500 ft. elevation gain. This is Strenuous to very strenuous physical activity. Prior experience and training is beneficial very, very helpful.
  • Class D: Hikes up to or over 15 miles round trip and/or greater than 3500 ft. elevation gain. These require very strenuous physical activity often including exposure or requiring use of technical skills. Knowledge based on prior experience and training is highly beneficial.

Additional Hike Information

If you also see the letter "E" after the classification (such as C-E or D-E), the trip involves exposure (i.e., risk of falling) and may require advanced climbing skills. If you have fear of heights or are unsure of your ability to handle exposure, you may wish to go on a different activity, or consult with the Trip Leader to get input from them.

Within each of the above letter classifications, hikes may also be described subjectively as Easy, Moderate, and Difficult in comparison to other trips of the same classification. Thus, a Difficult B hike is harder than an Easy B hike, but easier than a Moderate C hike.

“Exploratory” in the trip description simply means the leader has researched the route, but has not been there before. Participants should expect potential route-finding and not a clearcut/known trip.

The following shorthand descriptions may also be used to describe the difficulty of the terrain on a hike:

  • On Trail: The trip is mainly on improved trail in reasonable condition. Any portion of the trip not on trail is easy "like trail" conditions.
  • Off Trail: Below timberline (about 11,000 in Idaho), the trip may involve bushwhacking or travel through forested terrain. Above timberline, the trip may cross open tundra or involve
  • Class 2 hiking under the Yosemite Decimal System: i.e., moving on or around small boulders where the use of hands may be used, but only to maintain balance. No special hiking or climbing skills are required. Exposure is usually minimal or nonexistent.
  • Scrambling: The trip involves Class 3 climbing: i.e., climbing that is relatively easy with plentiful handholds. Although a rope is rarely required, Class 3 climbing may be intimidating for less experienced mountaineers. Always consider bringing and wearing a climbing helmet to ensure your own safety. A fall on a Class 3 route usually results in a minor injury, but can on occasion result in serious injury or death.
  • Semi-technical: The trip involves Class 4 climbing: i.e., within the realm of technical rock climbing, but with relatively plentiful handholds. Some people will desire a rope, but usually just for protection on the descent. Participants must wear climbing helmets. A fall without the protection of a rope on a Class 4 route usually results in serious injury or death.


Hiking and Mountaineering Trips

Peak Bagging in the Lemhi Range

Join us in exploring peaks above 10,000 feet in the Lemhi Range. Each day we will summit a peak or two and relocate to another trailhead for the next day's peaks. Participants will need the ten+ essentials in their daypacks, food, water, and car camping gear. The hikes are mostly off trail, up to 12 miles RT with over 5,000 ft elevation gain with some YDS Class 3 terrain. The general area is about a 4-hour drive from Boise on paved or good gravel roads, plus an hour or two on rough 4WD trails. We return to Boise on Wednesday, August 14. No dogs, please.

Boise Butterfly Count

Join us in the annual Butterfly Count, held across the country around the 4th of July.

We'll rendezvous in Boise to arrange carpools. Then we visit five different sites at higher and higher elevations. This is an all-day event; the count usually ends around 6 pm high in the Boise Foothills.

Based on past years, we typically see about 40-45 butterfly species over the course of the day (that's nearly one third of the butterfly species found in Idaho).

Ladakh: Culture and Climbing

Ladakh (“The Land of High Places”) sits at the crossroads of Tibet, India, and Pakistan. It is a place rich in history, culture, and it offers the amateur mountaineer a number of accessible Himalayan peaks. Join IMR member Scott Arnold as he shares with you his experience of climbing one of those peaks, Stok Kangri. In his presentation you will enjoy a glimpse into the culture and history of the region along with some useful tips towards planning your first 6,000 meter climb.

Ice Axe Self-Arrest and Glacier Travel Workshop

Join IMR for an overview of basic glacier and snowfield travel skills tentatively scheduled for Saturday, 20 April 2019 and run from 8:30am to noon (this date may change depending upon Bogus Basin's closing weekend schedule). Participants will have the opportunity to practice ice axe self-arrest, glacier travel on crampons, and rig a Z pulley system for a simulated crevasse rescue. We will also try our hands at a few key knots useful in climbing. This workshop is open to both the novice and to those looking to refresh their glacier travel skills.

Succor Creek Geology

Join Friends of the Owyhees for the 4th Edition of Succor Creek Geology

About The Trip

This trip we will be guided by Sammy Castonguay, geologist and owner of ThisMagickalEarth.com. Other local geologists may also accompany us. We will focus on basic rock identification and landscape observations to interpret the geologic history. Some rock hammers and hand-lenses will be available, but you may also bring your own.

Peak Bagging in the Seven Devils

Join us in exploring YDS Class 3E summits in the rugged and beautiful Seven Devils Peaks. On Sunday we will drive about 4.5 hours from Boise and carcamp on the way to the trailhead (accessible to passenger cars on a good gravel road). Monday we will backpack, partly off-trail, to a lake basin and set up base camp. That same day, we will scramble up the first of the peaks on our list. Tuesday, we hike off trail and scramble up a couple more peaks. Wednesday morning, one more short scramble is on the agenda before packing up, backpacking out, and returning to Boise.