Rab Firewall Alpine Waterproof Jacket review: a practically flawless rain shield for top-of-the-mountain adventures

Rab Firewall Alpine Waterproof Jacket: first impressions 

If you're in the market for a high-performing waterproof jacket for hiking and climbing, it makes sense to buy from a British brand since no one knows more about rain than the Brits. Rab has put all its expertise into this fine piece of gear.

The Rab Firewall Alpine is built for fast and light adventures where you're likely to come up against the worst of the weather. Made using a three-layer Pertex Shield construction, it performs as well as any hardshell, holding off a heavy downpour or a strong wind, while the peaked hood protects your face. There's no added stretch, but the fabric has some natural give, which allows for freedom of movement if you're wearing it for an expedition that involves climbing or scrambling.

The hood is easy to secure thanks to a toggle adjustment at the back, and stays up in a gale thanks, in part, to the protective high collar.

Despite its impressive wet-weather protection, it's highly breathable if you're wearing it on the move, and for milder conditions, easy-to-open underarm venting zips help you quickly dump heat.

It's one of the lightest jackets we've ever tested, so you won't notice it when you have to wear it all day, and it rolls up small enough to fit into your backpack or running vest when you're carrying it.

Because the goal is lightweight protection, the brand has foregone a bunch of pockets, opting instead for just one well-placed chest pocket that's deep enough for any smartphone. It's easy to reach when you're wearing a pack, and the two-way front zipper gives easy access to pockets and gear underneath the jacket.

It's a robust piece of kit that's likely to replace your favorite waterproof, and though it's pricey by most people's standards, it's actually on the more budget-friendly end of waterproof jackets we've tested.

Rab Firewall Alpine Waterproof Jacket: in the field 

After swearing by my Montane Phase Lite jacket for the past four years, I received this jacket to test just as summer weather rolled in. I wore it for a hiking and yoga retreat in the Swiss Alps, where it was surprisingly useful, and carried it (or wore it) on every summer hike in Scotland and in the Yorkshire Dales National Park, where I've been able to test it out against heavy downpours and light sprinkles.

Sizing, fit and comfort

I tested a UK 8, which, according to the label, is an XS in the US. I'm somewhere between a small and an XS, depending on the brand, but I'm glad I went with the smaller size as it fits me really well. It's neat enough not to be annoying, but there's still room for my fleece underneath.

I wouldn't say it's overly long, but it just covers my bum for a little extra protection, and the sleeves are long enough to hide my hands if I don't want to wear my gloves. They're not overly long, and they have hook-and-loop fastenings for adjustability.

When it's zipped up, the collar is high, so my face gets loads of protection against the wind. And the hood doesn't blow down, which is essential in Scotland.

Waterproofing and breathability

Because it's not a hardshell, I wasn't necessarily expecting it to be such a powerhouse against a deluge, but that's exactly what I've experienced.

On my first evening wearing it, I was walking through Verbier, and one of those evening alpine thunderstorms rolled in. I got absolutely hammered on my sprint home, but when I got indoors, I was shocked to see that I was bone dry on the inside. Like any waterproof, it would eventually wet out if I were in conditions like that for hours, but the Pertex membrane and watertight construction have yet to let me down on the trail.

I've been testing this in mild conditions because it's been summer, so I've had ample opportunity to expose any flaws in breathability, and I can't find any. I've worn it for a few hikes from start to finish and with the pits unzipped, I've been very comfortable.

Weight and packability

Montane has already released a light version of this jacket – the Firewall Light – and while it is heavier to make it more robust against summit conditions, we're only talking grams. This jacket doesn't feel flimsy, but it's very lightweight – a hair lighter than my Phase Lite and heavier only than my Kathmandu Trailhead Stretch, but the latter doesn't offer the same level of weather protection.

I can squish the Alpine Firewall down to about the size of my water bottle and squeeze it into my pack, whether I'm hiking with a light 20L day pack or a 33L with more gear.

Storage and fastenings

One of the reasons this jacket is so light is that it only has one pocket, which some might view as a downside, but it doesn't bother me.

We've been trained to expect hand warming pockets on jackets, but the moment you fasten the hip belt on your backpack, they're totally pointless. So Rab has done away with them here and just included a zipped chest pocket where you can keep your phone for easy access – that's all I want.

The front zipper is two-way, so if you do use your hand warming pockets on your mid layer, you'll be able to access without having to completely unzip in a rainstorm. Plus, there's an extra popper at the bottom for more protection.

You can tighten the cuffs with hook-and-loop fastenings, while toggles on the back of the hood and hem mean you can cinch everything in tight, though the neat fit has meant I haven't had to.

Also consider

Comparison table

• How Advnture tests products