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

Mount Baker Mountaineering

What do you do when you turn 50? Commit to a climbing project that includes all of the major Cascade Volcanoes, that's what. IMR member Scott Arnold has been chipping away at his goal for the last six years and he is looking forward to sharing his experience on Mt. Baker with you. In his presentation, Scott will offer a few of his pictures from the climb, provide route information, teach a few basic knots useful to mountaineers, and he will bring some of the gear that you might want to have on hand when you make your attempt on this Cascade giant.

Succor Creek Geology Tour

This trip we will be guided by Sammy Castonguay, a geologist with Treasure Valley Community College and Andrea Bowen a geologist for the BLM. Some equipment to survey the geology will be provided.

Expect 3-6 miles of hiking in rocky terrain/uneven ground with an elevation gain and loss of 1000 feet . Expect cool day and chilly nights. Expect to have mud in spots on the trail.

Birch Creek Corral Project Pt. 2

Come and join the Friends of the Owyhee to work with the Bureau of Land Management to repair an old corral that is on the National Register of Historic Places at Birch Creek Historic Ranch located on the Owyhee River. This event runs from Friday 27 October at 4pm to Sunday 29 October at 4pm.

For more information and to sign up please go to


Wallowa Mountains Traverse

Join us in exploring the lakes and summits of the Wallowa Mountains in Eastern Oregon at moderate elevations (5,000 ft. to 9,500 ft.) as we backpack about 60 miles on trails. We will average about 10 miles and 3,100 ft. elevation gain per day; our longest day will be about 12.5 miles and 4,200 ft. cumulative elevation gain. We have backpacked part of our planned route and are keen to revisit and to explore more.


Join us in viewing the solar eclipse from a summit that is over 10,000 feet in elevation. On Sunday we will drive from Boise to our trailhead in the Lost River Range and backpack up to 4 miles with 3,300 feet of elevation to our high and dry camp. On Monday morning we'll hike about a mile (with about a 1,500 foot gain) to the summit in time for the eclipse, backpack out and return to Boise.

Butterfly Count

Help monitor butterfly population trends in areas near Boise, including Military Reserve and Bogus Basin. Participants should be prepared for a day of hiking: daypack, sunscreen, lunch, snacks, water, sunhat, and sturdy footwear. A butterfly net is helpful but not required, as is a clipboard and tethered pen.

A registration fee of $4 per person will be collected; the fee helps the North American Butterfly Association compile the results of this nationwide survey.