This post may contain affiliate links.

The ULA Circuit as a Winter Backpack

ULA Circuit as a Winter Backpack

The ULA Circuit is one of the most popular thru-hiking and backpacking packs available today. It’s a conventional ultralight style pack with an open front mesh pocket, a roll-top closure, a spacer mesh back panel behind the shoulder straps, and large side water bottle pockets. My favorite feature of the pack is its wide hip belt, standard on ULA’s overnight packs, which provides excellent load-to-hip transfer and some vertical adjustability so you can dial in a very good fit. For a complete breakdown of the features of the ULA Circuit, see the ULA 24 Ultra Circuit Review I wrote early this year for the blow-by-blow. The only difference between the Ultra Circuit and the Robic Nylon Circuit I evaluate below for winter use is the fabric the packs are made with.

Specs at a Glance

  • Total Capacity: 68L
  • Closed Capacity: 47L /2900 cubic inches (main body and extension collar)
  • Max recommended load: 35 lbs
  • Pack Body: Robic Nylon, Spacer Mesh
  • Weight: 37.3 oz / 1038 g

ULA contacted me to ask whether I’d review the suitability of the Circuit for winter backpacking since that’s something we’ve been doing at and writing about for a long time. Now, winter backpacking means a lot of different things to different people in terms of weather conditions and equipment needs, so let’s get specific.

Winter Backpacking and Packing Requirements

Winter backpacking gear is bulky and has to be carried on the outside of your pack.
Winter backpacking gear is bulky and has to be carried on the outside of your pack.

Three-season backpacking or thru-hiking is typically done in comfortable weather, with good beta when it comes to trail conditions and water sources. But that’s not the case with winter backpacking where there is much less certainty about what you’ll encounter. Temperatures are usually below freezing, winter days have much less sunlight, most water sources are frozen and it’s difficult to predict what backcountry trail conditions will be like in terms of snow depth or ice.

Weather conditions can also vary widely, especially at elevation, where high wind speeds and wind chill increase the danger of frostbite or hypothermia unless you carry extra insulation and face protection. You should expect to make frequent layer changes to avoid overheating and sweating, but it’s important to minimize stopping to avoid becoming chilled because you’re not moving. Winter food requirements are also significantly different because winter backpacking uses roughly twice the number of calories as non-winter hiking. Since you can’t eat all the calories you’ll need during the day at breakfast or lunch, it’s important to snack very frequently and to have your food easily accessible so you can eat on the move.

A top lid, dual side compression straps, and a bottom sleeping pad straps make a winter pack much easier to use.
A top lid, dual-side compression straps, and bottom sleeping pad straps make a winter pack much easier to use.

From a packing perspective, this means that you have to carry a lot more weight in terms of food, water, and fuel. You’ll want to bring more sleep insulation, dry clothing, and multiple pairs of gloves, and hats because it’s difficult to dry clothing in the cold. Finally, you can expect to carry several very bulky objects that can’t fit inside your pack like snowshoes, a foam sleeping pad to sit on when melting snow and cooking, traction aids like microspikes, and in many cases additional gear including crampons, an ice axe, avalanche shovel, climbing gear, or ski equipment. This additional equipment can necessitate switching to a winter backpack that can carry more weight, has more closed storage and access methods, and has better external attachment points for carrying bulky gear.

Desirable Winter Backpack Features

At a minimum, backpacks should have dual side compression straps to be winter capable.
At a minimum, backpacks should have dual side compression straps to be winter capable.

Winter-specific backpacks and three-season backpacks that are easy to use for winter backpacking come with features that make it easy to carry and access winter-specific gear.

For example:

  • A top lid pocket is virtually a must-have for winter use since it can hold extra gloves, hats, goggles, and face protection that you want ready access to during the day without having to open the main compartment of your backpack to access them.
  • A floating top lid is a real asset because it can be used to hold gear piled on top of the main pack bag in place like a coil of rope, a sleeping pad, a tent body, or even snowshoes.
  • Numerous external attachment points like dual-side compression straps with glove-friendly buckles are good for carrying bulky gear or items with sharp points like a foam sleeping pad, a shovel, snowshoes, or crampons. You can’t put these items inside the backpack because they’ll take up too much space, they can’t fit, or they’ll be covered in snow and ice (as you switch between them) and you don’t want them making all your other gear wet.
  • Bottom sleeping pad straps for lashing a pad or tent body to the base of a pack are useful. I typically carry two sleeping pads in winter: an inflatable one for sleeping on and a foam pad to sit on while cooking and melting snow. The latter is a good fallback in case the inflatable pad leaks and also makes a good emergency splint or ground insulation if someone is injured.
  • Daisy chains are external gear loops for clipping items to the outside of a backpack from extra webbing straps and external pockets to insulated water bottle sleeves.
  • An external crampon pocket makes it easy to carry microspikes or crampons so they’re easily accessible while keeping the sharp points away from your body and other gear in case you fall.
  • Side zippers let you access or stash insulation layers in the main compartment without having to open the top. This is especially handy on a high-volume backpack over 70L in volume.
  • Ice axe loops and shaft holders to secure axes to the outside of the pack.
  • A hipbelt with a big center buckle that does not fill with snow and can be used while wearing gloves.
  • A snowshedding back panel and hipbelt padding.

How Easy is the Circuit to Use for Winter Backpacking?

If your version of winter backpacking resembles the winter backpacking requirements I list above, the Circuit is awkward to use, particularly when compared to winter-specific backpacks like the Osprey Mutant 52 or the Black Diamond Mission 75. Other lightweight backpacks like the Granite Gear Blaze 60 or the Granite Gear Crown3 60 are also substantially easier to use because they have dual compression straps on three sides and optional floating lid top pockets than can deployed over their rolltop pack bags, so you have the best of both worlds depending on the season.  (See Also: 10 Best Winter Backpacking Packs)

That’s not to say that you couldn’t hack the Circuit with third-party webbing straps to create better attachment points, but the current pack design is still limited in that regard as we discuss below.

Mesh back panel and hipbelt padding

The Circuits back panel and the inside of the hip belt is covered with a porous mesh that picks up snow when you put the pack down. This melts on your clothing when you put the pack on and makes it wet, which is very undesirable in winter. 
The Circuit’s back panel and the inside of the hipbelt are covered with a porous mesh that collects snow.

The Circuit’s back panel and the inside of the hipbelt are covered with a porous mesh that picks up snow when you put the pack down. This melts on your clothing when you put the pack on and makes it wet, which is very undesirable in winter.


When you put the Circuit hipbelt on you need to tighten it by pulling on four webbing straps that tension the belt using ladder locks. This can only be done by removing your gloves in winter because you need a fine degree of dexterity to grab the ends of the webbing. A simpler hipbelt with a much beefier center buckle that does not clog with snow is more desirable.

No external closed pockets

All of the storage on the Circuit is in the main pack bag, so there’s no place to put extra gloves, mittens, hats, goggles, or face protection inside the pack without stopping, opening the pack bag, and retrieving these items. You can’t put the in the front mesh pocket because they’ll get wet there and become useless. While you can put snacks into the hip belt pockets, they’re not large enough to hold this extra accessory clothing. The only alternative is to add a large 3rd party chest pack attached to the front shoulder straps.


Its awkward to carry snowshoes along the side of the pack because there is only one side compression strap and it doesn’t close with a side release buckle.
It’s awkward to carry snowshoes along the side of the Circuit because there is only one side compression strap and it doesn’t close with a side release buckle.

The most efficient way to carry snowshoes is along the sides of a backpack, close to your hips. This is easy to do with backpacks that have dual-side compression straps with glove-friendly side-release buckles. Unfortunately, the Circuit only has one side compression strap, that closes with a glove-unfriendly ladder lock and a short webbing strap that is only barely long enough to secure a foam pad to the side of the pack with one end in a side pocket. There’s also no way to add your own side straps because there are no gear loops sewn into the vertical rear seams along the side of the back panel.

There are no good anchor points to attach an insulated water bottle sleeve to the Circuit if the side pockets are in use or covered by other gear.
There are no good anchor points to attach an insulated water bottle sleeve to the Circuit if the side pockets are in use or covered by other gear.


If you’re looking for a backpack that can span four-season use and your winter conditions dovetail with the ones described above, I wouldn’t recommend getting the ULA Circuit. It’s just not set up for flexible winter backcountry use. It’s fine if you only need to carry microspikes or crampons over a short snow-covered section of trail, but it’s not easy to pack when you have to carry a variety of snowshoes and mountaineering tools for any length of time. I also don’t think it’s really worth trying to reengineer the Circuit to be four-season ready. There are just too many feature and structural changes required that it’d probably be more expeditious to design an entirely new pack on the pre-existing Circuit or the larger ULA Catalyst frame.

I hope this analysis was at least useful to give you a taste of what to look for in a winter-capable backpacking pack and pointers to packs, including lightweight backpacks, that can span four-season use.

Disclosure: ULA donated a Circuit backpack for this article.

SectionHiker is reader-supported. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.


  1. Great brakedown. The circuit is a great pack but definite NOT up to snuff for winter use.. I’m surprised ULA ask you to review it in that light. It makes me question whether they know anything about pack design. I mean, this isn’t rocket science. I have a Granite Gear Crown2 and it is so good for winter use. Bought it on your recommendation and it’s so easy to use.

    • They probably don’t know that Philip is not willing to lie to his readers to make a buck. Thanks for keeping it real PW. If you want honest assessments of backpacking gear, warts and all, SectionHiker is the best!

    • They know a great deal about pack design and my interactions with them have been very positive and ethical. They may not know a lot about winter backpacking, which may be why they asked Philip to determine winter backpacking suitability.

      • Cheri, I think it’s a fair question actually. ULA is on its 3rd owner in the past 10 years and none of their backpacks have changed in that time with the exception of fabrics and colors. The guy who designed the original ohm, circuit , and catalyst wasn’t even a company employee. So do they have a pack designer on board or not? It’s hard to say. But you can look at any other company’s winter packs (Osprey, HMG, TNF, etc) and quickly figure out what is needed for winter use. Experience does help but common sense often works just as well.

    • Maybe ULA is looking for ways to upgrade their pack for winter use? I have the Circuit but for spring- fall excursions.

    • I’ve owned a circuit for a few years and it’s the best pack I’ve ever owned for my use. extremely comfortable up to about 40 lb. when I was choosing it I contacted Peter at ula and he was very helpful and informative. they do know a lot about pack design. my take on this is it they are thinking about coming out with a winter version of the circuit and wanted to get an expert review so they know what changes would be needed. Philips excellent and detailed review gives them a lot of things to consider should they decide to design a winter circuit

  2. In the context of winter backpacking in the southern Appalachians it works great because it’s just a 3+ season setup compared to somewhere much colder. Anything short of a massive nationwide cold front I’m just throwing in micro spikes and extra clothes, anything more and I really shouldn’t be out there. I’ve had issues with the mesh and hip belt freezing up exactly like what is stated.

    • Exactly. That’s why I went to great lengths to qualify what I mean by winter backpacking. If it’s just spikes and extra clothes, no problem. But when you have to carry bulky winter gear for the northeast or mountainous terrain, the Circuit just doesn’t cut it. Anything over 60L from Osprey is better by a mile.

      • In addition, there is a trend amongst UL pack makers to put small buckles on their backpacks. That’s the last thing you want in snow because the buckles fill with snow and cease to work.

        • I forgot about the buckles, that’s also been an issue and something to DIY on my catalyst. Had to hike out no hip belt several times.

  3. the exact reason why I sold mine.
    using the mountain equipment tupilak now & it works great for everything from ultralight backpacking over mountaineering to alpinism. not the most comfortable pack but with a few tweaks like putting a thin foam pad in the back it is very versatile

  4. Been using my circuit as my winter pack for about a decade since downsizing to a lighter pack for three season use. I like the flexible way I can carry snowshoes, including strapping them down vertically with side straps so they don’t stick out horizontally.

  5. The Circuit is my “section hiking with my wife” pack. It provides ample room for large food hauls and a two person, hiking pole tent. For winter, I took your advice and bought the Granite Gear Blaze 60, and although it is a pound heavier, it has the proper straps to haul snow shoes, etc. Very happy with it.

  6. Thanks for the reinforcement. I love my Circuit, but not in the winter. It turns into a big awkward snowball, and makes everything wet and cold. I gave up after one try, and got my big heavy Osprey Aether out. It weighs a ton, but it is so easy to stay warm and dry that I don’t mind. Thanks, Philip!

  7. Thanks philip, Your one of only a few honest reviewers out there!
    My circuit carry’s all my climbing gear for three seasons of use. But for winter I rely on my dependable heavy duty Mountain Hardwear AMG 55 pack! I liked it so much I bought the AMG 75!!

Leave a Reply

Your email address will not be published. Required fields are marked *