Best Mountaineering Backpacks
Best Overall Mountaineering and Alpine Model
Osprey Mutant 38
Once again, we've chosen the ever-impressive Osprey Mutant 38 as our favorite mountaineering backpack. The pack's current mutation is even better than the last, with improvements to utility, versatility, durability, and climbing comfort. This is a pack that can morph from a gear-hauling beast to a light and nimble summit pack in mere moments. It has an excellent suspension for heavier loads and logical and useful climbing features for technical pitches.
Many climbers still retain some skepticism toward Osprey as a manufacturer for technical climbing packs. We did, too. Some of their packs have too many features and so many straps that they slap you in the face when you're on the hardest part of the climb. This pack has more features than some, such as the Patagonia Ascensionist 40 or Arc'teryx Alpha FL 45, but it can be slimmed down to become comparable with the simplest and lightest packs in this review. Overall, this is an excellent update to an already awesome mountaineering pack. And in this review, be sure to also check out the Osprey Mutant 52, which fills a void in our backpack quiver as the most comfortable mountaineering backpack of its size. The Mutant series is now relevant to longer and more complex, colder, or more gear-intensive climbs.
Read review: Osprey Mutant 38
Best Bang for Your Buck
Patagonia Ascensionist 40
The Patagonia Ascensionist 40 is slightly more expensive than the overall winner, the Osprey Mutant, but it's so versatile that we feel it offers a better value. This is an excellent mountaineering backpack for a variety of uses. It strikes a middle ground between the other two winners—the fully-featured Mutant and the streamlined Arc'teryx Alpha. It has a few extra features like side straps, small hip pads, and a useful zippered top-access pocket, but they add minimal weight or complexity penalties. This pack is comfortable when loaded down for the approach yet lightweight and graceful during the technical climbing.
Naturally, there are a few compromises in the design for this pack to be so versatile. If you want the absolute lightest pack, the most comfortable option for a long haul, or a little more capacity, you might look to our other award winners. For a true Pack-of-all-Trades, this one does very well, and if you are hoping to avoid accumulating an absurd quiver of climbing backpacks, this one can cover a lot of adventure types.
Read review: Patagonia Ascensionist 40
Best for Longer Trips
Osprey Mutant 52L
The biggest pack in Osprey's Mutant series, the Mutant 52, adds valuable volume to our longtime favorite, the Mutant 38. The features are very similar, and the pack even retains most of the climbing comfort of its smaller relative. This is a great mountaineering pack for those who want a fully-featured backpack that is still lightweight enough for challenging, steep, technical terrain. If you've been dreaming of a Mutant pack for trips over 3 days in length, for colder weather climbs, or for objectives with considerable complex terrain, this is likely your dream come true.
The newfound volume of the 52-liter version does come with a couple of pitfalls. When pared down for a summit push, the 52-liter pack is not as compact or comfortable as the smaller 38 or 22-liter versions. It does very well, however, in sustained moderate alpine terrain. We also found the asymmetrical collar difficult to overstuff and would prefer a more traditional cylindrical collar, since it would be easier to cram things in and then cinch it closed and compress with the lid. Overall, this pack sets a new bar for technical climbing performance in higher volume backpacks.
Read review: Osprey Mutant 52
Best for Fast and Light
Arc'teryx Alpha FL 45
The Arc'teryx Alpha FL 45 excels at fast-and-light missions. This is the third time the Alpha has won an award in our reviews. This mountaineering backpack rewards the savvy packer with an excellent weight-to-volume ratio and impressive durability, especially considering its ultra-lightweight. We think of it as a 30-liter pack that can be overstuffed with light, bulky items for a short hike to basecamp when minimizing weight on the climb is a top priority. It is perfect for car-to-car alpinism, and manageable for 1 to 3-night trips in the summer if you have a very light bivy kit. On technical climbs, it feels like a dream. The fabric is extremely durable and can even stand up to some light hauling.
This pack makes some compromises to achieve such impressive climbing comfort at such minimal weight. It is not a fully-featured pack, so it requires some fiddling and creativity if you want to strap on things like trekking poles, pickets, or skis (not recommended). To get to base camp, you need to pack very mindfully to make sure it will carry comfortably. This will also only work if you have a very lightweight kit. Overall, this is a niche pack best suited to technical alpine routes with mixed ice and rock, so it's not the most versatile in this review. But it is the mountaineering backpack of choice for alpinists who want to do more with less. It's the model our testers consistently pulled out of the pile when gearing up for difficult routes.
Read review: Arc'teryx Alpha FL 45
Best for On Route
Black Diamond Blitz 28L
Although the Black Diamond Blitz 28 fills a similar niche to the Arc'teryx FL 45, we think it deserves its own nod here as an excellent and affordable addition to your mountaineering pack quiver. This pack is simple, light, and small — making it an excellent companion on routes where you are pushing your grades and trying hard. This pack is the only one in the review that we would want to take in the mountains as well as on long multi-pitch rock routes, using it similarly to a small on-route climbing backpack like the old Bullet from Black Diamond or the Bug from Petzl.
There are numerous issues with this pack, notably the durability and its lack of versatility for all types of mountaineering. It's unlikely you would want to take this pack ski mountaineering, though you may enjoy its lightweight simplicity for a mellow day of backcountry skiing. And you'll want to be careful how you pack the bag, so you don't create too much abrasion from protruding objects. In general, this backpack is noteworthy for filling a valuable niche at a decent price.
Read review: Black Diamond Blitz 28
Best for Expeditions
Gregory Denali 100
The Gregory Denali 100 shines for its comfort and versatility on expeditions. We appreciate the Denali for how comfortably it sits on your back. In the places where it does rise above your head, it does not impinge your view or range of motion. We also liked the snow-specific features on the Denali, since most packs of this size are likely to encounter snow at some point during an expedition. And, when packed well, it feels secure and streamlined while still allowing easy access to items via large zippered sleeves and pockets.
It should be noted, however, that this isn't a featherweight pack meant for a wide variety of expeditions. Gregory built it for Denali, and it does that job well.
Read review: Gregory Denali 100
Analysis and Test Results
This is a review of mountaineering backpacks for technical alpine climbing. The packs are equipped with features useful for everything from traditional mountaineering with ice axes and crampons to alpine rock climbs, ice climbs, or even ski mountaineering. The main difference between these packs and ordinary backpacking packs is in the feature set. These packs are made to carry crampons, ice axes, ice tools, ropes, and potentially skis. They also vary in their shape, size, and carrying comfort.
Mountaineering packs are often identifiable by their svelte exterior. They sport minimal straps or excess material that can whack you in the face when it's windy up high on a ridge. These packs are more streamlined and hug close to your body to improve mobility and climbing comfort, and they are made of light but durable materials.
The ideal alpine climbing pack for most venues in the U.S. should be relatively easy to overstuff with several days worth of food and basecamp necessities. Then it must be able to slim down for technical climbing. We want a pack to be streamlined for climbing, but we don't want to so beat up from carrying an awkward load to basecamp that we are aching during the climb itself.
These packs don't have lots of pockets, straps, access points, or beefy suspensions. We scored each mountaineering backpack on the criteria detailed below using a standard scale of 1 to 10.
We selected a wide range of mountaineering packs for this review. We recognize that alpine climbs come in all shapes and sizes and offer a glimpse into some of the best packs for everything from in-a-day alpine missions to multi-week expeditions. Most of the packs in this review are in the 30 to 50-liter range, which is a great all-round size. You will find a few outliers, however, notably the Gregory Denali expedition pack, and some "tweeners" as well. All this is to say — there are a lot of caveats and tradeoffs in choosing a mountaineering pack, so be sure you're selecting the right tool for the task. Each review thoroughly discusses the best applications for each pack to help point you in the right direction for your climbing passions.
Our performance scores aim to shake out the best packs from the mediocre ones. Just like cream, the best rise to the top of the chart. These performance scores, however, do not take price into account. Rather, we want to know what the best packs are without biasing our assessment due to the price tag.
After we figure out which packs are our winners, it's time to figure out just how much you want to spend, and how much versatility your pack needs to provide. The top-scoring Osprey Mutant offers excellent value, but we think the Patagonia Ascensionist is the real ringer here. It excels at everything from laidback crag days to hard-core summit bids, and it can significantly cut back the number of packs you might need in your pack quiver.
Mountaineering is a physically and technically demanding sport. It forces you to carry everything necessary to survive in a harsh mountain environment with you at all times. But if you carry too much weight or a load that's too bulky, you can compromise your balance on technical maneuvers or deplete your endurance stores. This makes the weight of your pack and the volume it can comfortably carry of the utmost importance.
We list each pack's weight-to-volume ratio. But we didn't take the manufacturer's word for it. We measured the volume ourselves with the help of hundreds of ping-pong balls to get an apples-to-apples (or pings-to-pongs) sense of what each pack could handle. We also measured the weights ourselves, with a digital scale.
Due to the differences in volumes between packs, it's possible that a smaller model made from heavier materials could still be lighter than a more substantial contender built from lighter-weight materials. To account for this we use a weight-to-volume ratio to help us better compare the pack weights irrespective of pack size. We measured the weight of the whole pack in grams (g) and volume of the main compartment in liters (L) (note: we did not include the volume of the lid or any pockets because loading pockets can throw off a pack's balance). This helped normalize our measurements across all manufacturers because some report volume including pockets while others do not. This score shakes out when we get to features, where packs with lots of pockets scored higher in an objective sense. If you hate pockets, you can look with skepticism upon a highly featured pack.
For a more realistic test, we also assembled a sample kit for a weekend of summer alpine climbing. We then tried to pack this gear into each of the packs. Although this test was less useful for the expedition packs, which gobbled up all the equipment and then some, it gave us an intuitive visual way to compare practical volume. It also helped us to evaluate attachment systems for crampons, ice axes, poles, ropes, helmets, etc.
Weight is the first thing to consider when selecting gear for alpine climbing and mountaineering, so it's also the first of our scoring criteria and receives the highest percentage in the overall score. The Arc'teryx Alpha FL 45 ran away with the best ratio in both calculations—measuring volume with and without the extendable collar. The Hyperlite Mountain Gear 3400 Ice Pack, however, was very close behind. The Black Diamond Blitz 28 is an excellent on-route climbing pack to add to your quiver for those more challenging rock and ice routes where you want a pack that can really slim down and stay out of the way on the climb.
For this review, we measured the weight of the Osprey Mutant 38 without the lid. Due to the increasing number of packs that forego lids, we felt the added weight was an unfair penalty to the Mutant, especially since the lid can be removed and the FlapJacket deployed, which leaves it very similar in design and function to the Patagonia Ascensionist. For the 52-liter Mutant, we left the lid on because it is a larger pack designed for more carrying capacity.
There are two important components to mountaineering pack comfort—comfort on the approach and comfort on the climb. Smaller packs with flexible (or minimal) frame sheets tend to be more comfortable on technical climbs than larger, beefier packs. Larger packs, in contrast, usually have more substantial suspension systems, frame sheets, stays, and padding. These tend to make the approach more comfortable than an overloaded fast-and-light pack but can feel cumbersome on technical rock and ice routes.
We are seeing more and more mountaineering backpack models with flat back panels and simple suspension systems. Pack manufacturers are increasingly eliminating the lid and even the load lifter straps on top of the shoulder straps. At first, we were skeptical, worrying that this design change would boost climbing performance at the expense of comfort on the approach. As we found out, however, this is not entirely true.
First, let's point out that the more traditional Osprey Mutant 38 is still the most comfortable with heavy loads. It has a minimal frame, but can carry up to 50 pounds with ease (as easy as carrying 50 pounds on your back can be, anyway).
Let's also look at the surprising performance of our other two comfort winners, the Arc'teryx Alpha FL 45 and the Hyperlite Mountain Gear 3400 Ice Pack. Both of these have relatively flat and flexible frame sheets. They rest flush on your back and can, therefore, move fluidly with you through any terrain. This close contact with your back distributes some of the load, spreading it away from your hips and shoulders. They then add straps to tilt the weight one way or another to balance it. It's simple, and it works.
To better help us understand why this works, we consulted with a physical therapist and climber who helped us make sense of it. To summarize, traditional packs with lumbar support push your spine into extension, which is a strong structural position for those unaccustomed to carrying a backpack. It doesn't work as well, however, for fit alpine climbers. Instead, it locks our bodies in one position, making it harder to move. Greater flexibility, in contrast, allows us to fully exhale, rotate our torso more thoroughly, and tilt our pelvis backward, making high stepping much easier. This means you have to fight the shape of the pack less, thus saving energy.
Another critical reason why these simple pack designs seem to work is the concurrent increase in ultralight, durable climbing equipment — particularly sleeping pads, sleeping bags, and shelters. Add all of this together, and we can go further while carrying less weight.
Offwidths and mixed chimneys, bushwhacking, careless crampon use, stuffing bags to their gills—alpine climbing can subject a pack to all sorts of wear and tear. But when our testers are in the mountains, they like to focus on climbing instead of babying their equipment.
Fabric durability is commonly assessed using a "denier" number, which is the linear mass density of fibers. In other words, a higher denier number usually denotes a thicker, more durable fabric. A lower number fabric will be thinner and typically lighter weight. This rating, however, doesn't tell the whole story. The primary durability issue for mountaineering backpacks is their fabrics' abrasion resistance. Manufacturing technics, terms, and treatments can make this tricky to parse out.
In general, most mountaineering packs use fabrics with adequate durability for alpine climbing. Some stand out above the rest, such as the impressively durable Arc'teryx Alpha FL 45, while others fall behind the curve, like the Hyperlite Mountain Gear 3400 Ice Pack with its easily-abraded Dyneema.
Hyperlite Mountain Gear packs are made from Dyneema or Dyneema/polyester hybrid fabrics. Bare non-woven Dyneema (NWD, also known as Cuben fiber) is exceptionally lightweight, waterproof, and boasts tremendous tensile strength. But NWD has a weakness: abrasion. For this reason, manufacturers using NWD often use it in a hybrid fabric, laminating it with a woven face fabric to improve abrasion resistance. The Hyperlite Ice Pack is constructed with a NWD/polyester hybrid fabric. Our tests found this to be less resistant to abrasion than the more traditional nylon fabrics in this review.
Many pack manufacturers use fabrics with a lower denier on the sides and top of the pack to save weight. Then they place heavier, higher denier fabrics on the bottom and on other high-impact areas, such as crampon pouches. Our testers found, however, that when climbing in typical alpine terrain, the sides of the pack do get scratched up. The only part of a pack that really seems to not see abuse is the part that's against your back.
For this reason, we like the consistently durable materials used throughout the Patagonia Ascensionist. We also appreciate the padding on the bottom, a frequent site for pack wear and tear. The Black Diamond Mission 75 is also an excellent example of durability with 420-denier nylon throughout.
Of more concern in the durability department is the strain put on specific areas of the packs due to design and construction. We inspected each model for notable stress points, and any stitching that looked like it might give out over time. Will the compression straps tear out of their seams under bulging loads? Does that initially cushy hip belt wimp out over time? Imagine a worst-case scenario — you arrive at the belay, clip your pack to the anchor by its haul loop, only to have that rip out, and your pack fall hundreds of feet to the deck. The Patagonia Ascensionist is an impressively durable pack for this reason as well. The entire suspension is sewn deep into the skeleton of the pack, making it one of the most solidly reinforced models we have tested.
Our testers demand a lot from their climbing packs. We want them to be comfortable hauling loads on the approach like a backpack, but not hinder our movement once we're on route. We scored each pack based on its ability to adapt. Versatility also influences whether you'll have to buy three packs for all your adventuring needs, or if you can get away with one Jack- or Jill-of-all-trades.
The Patagonia Ascensionist 40 and Osprey Mutant 38 ran away with top scores for versatility. The Ascensionist's wide, easily cinched mouth makes it a great for day-to-day cragging and expeditions alike, and it is burly enough to stand up to mountains of abuse. The Mutant scores so well due to its impressive comfort hauling heavy loads combined with its ability to shift effortlessly onto technical terrain. If you tend towards shorter trips, we'd steer you towards the Ascensionist. The Osprey does better when slightly overloaded.
If you find that you love the 35-liter pack size but you consistently stuff it to the brim, you may consider the next volume up from Osprey, the Mutant 52. Although it doesn't climb on route quite as well as its smaller cousins, the 38 and 22-liter versions, it does very well on longer trips and more complex, gear-heavy climbs.
Some packs allow you to remove the frame sheet to reduce weight or to use as an emergency foam sleeping pad. This is a feature we liked in both the Patagonia Ascensionist and the Black Diamond Mission 75. However, removable frame sheets are seemingly not as common as it used to be, likely because pack manufacturers are finding other ways to improve the comfort-to-weight ratio. For larger models, this can be an excellent feature to know about. We especially liked this feature on the Gregory Denali 100 since you will want to take a foam pad with you on summit day on most high-altitude expeditions. This is pad integrated into the Denali and means one less item to add to your summit pack. Though the process to strip down the Mission 75 took longer than others — it resulted in a very streamlined summit pack that climbed well.
Some manufacturers seemingly went overboard while trying to make their packs more versatile. For example, the Mammut Trion Pro has two different ways to attach two ice tools or axes, which adds weight. The Trion is undoubtedly a decent pack for everything you might want to do in the mountains, and its many features add weight as well as carrying comfort. Everything seems to be a compromise on this pack, and it is not optimized for anything in particular. (Though it does have a distinct proclivity toward snow sports with the external zipper pocket that makes sense for avalanche rescue gear).
The Ortovox Peak Light 32, however, is very well optimized for ski mountaineering, making it a bit less versatile but very well suited to its purpose.
Simplicity can be a great feature in a climbing pack. Well-designed alpine climbing packs are more streamlined than your standard backpack. Unnecessary features add weight and complexity while only amplifying the number of things you can break. For this reason, we gave points to packs that provided only the features necessary to complement the design of the pack.
On the flip side, as long as the pack features are useful and don't detract from functionality, we rate the pack highly in this metric. As such, Osprey hits it out of the park with the Mutant 38. Osprey has a long history of making packs with excess features, often to the dismay of climbers who want a simple cylinder with minimal straps. The Mutant has both surprised and pleased many climbers and mountain guides, allaying years of accumulated skepticism with the well-designed, durable, versatile, and impressively comfortable Mutant.
The Patagonia Ascensionist provides some competition though, boasting a lighter weight per volume than the Osprey, and retaining a lot of the useful features we like in the Mutant. Watch out Osprey. There's competition on the horizon!
Ortovox introduced an interesting take on features for ski mountaineering with their Peak Light 32. Although it ultimately wasn't a competitive backpack, it did fit its purposes very well with durable materials, a front access zipper, and an extra ice axe holster on the front of the shoulder strap.
Finding the ideal mountaineering backpack for your needs is a complex calculation of utility, durability, and comfort. The metrics we use in this review attempt to weigh several of the most important qualities of a mountaineering pack. We spent months comparing them, side-by-side, as objectively as humanly possible. We hope that the descriptions of our experiences in the field help you to zero in on the pack of your dreams.
Keep in mind that our top-scoring packs may not suit your needs perfectly. Be sure to check out packs that score the highest in the metrics you care about the most. We have also included a wide variety of pack types in this review, but our metrics still reflect a solid performance for each pack in its specific niche of mountaineering. For example, we didn't disadvantage expedition packs for being bigger. We assess relative sizes by looking at weight-to-volume ratios to better describe the quality of materials and thoughtfulness of design.
We hope this review helps you find the pack of your dreams!
— Lyra Pierotti & Ian McEleney