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Western Mountaineering Flash Vest REVIEW

The lightest down vest on the market, with a full zip but no neck coverage.


by Don Wilson | 2006-05-16 03:00:00-06

Western Mountaineering Flash Vest REVIEW


I've been itching to get my hands on a Western Mountaineering Flash vest ever since Western Mountaineering announced the product last year. The Flash aims to set a new standard in lightweight insulation with a specified weight of only 3.5 ounces (100 grams). With every feature aimed at shaving a few grams, the Flash vest gives up some comfort. But does it matter when you get a down vest at this weight?

What's Good

  • The lightest down garment on the market
  • Superb loft to weight ratio (0.45 inches/ounce)
  • Full zipper
  • Stuffs down to the size of a baseball
  • Good torso and shoulder coverage

What's Not So Good

  • No collar
  • Elastic hem rides up on your waist
  • Heavier than the specified weight



Western Mountaineering


2006 Flash Vest


Full zipper vest


4.4 oz (125 g) measured weight size L; manufacturer's specification 3.5 oz (99 g)


2.0 in (5.1 cm) double layer loft, as measured

  Loft to Weight Ratio

0.45 in/oz

  Shell Fabric

0.9 oz/yd2 (31 g/m2) nylon taffeta


850 fill power goose down, sewn through construction


Full zipper, reflective trim




The Flash vest is lighter than many windshirts; Western Mountaineering specifies the average weight of the Flash vest as 3.5 ounces. Our sample is a size large and weighs a bit more, at 4.4 ounces, but this is still an impressive amount of warmth in a small package. The Flash uses sewn through construction and a limited feature set to provide a fantastic loft to weight ratio. The Flash has a full zipper, no collar, a fairly large v-neck opening, no pockets and simple elastic for the hem and armholes.

The Flash vest packs its insulation into a square grid of sewn through down compartments, with each compartment about 3 inches per side. With 850 fill power down, the Flash lofts up to 2 inches of double layer loft. The loft to weight ratio of the Flash is 0.45 inches per ounce - the second highest loft to weight ratio of any garment tested by Backpacking Light. Only the Western Mountaineering Flight vest has been measured by Backpacking Light at a higher loft to weight ratio. I found the loft very even across the whole vest, with no obvious low points and continuous loft in each down compartment to within 3/8 of an inch from the edge of each compartment. The shell is a 20 denier, 380 thread count, 0.9 oz/yd2 nylon taffeta. The shell is also DWR treated. The full zipper is easy to use and is not backed by a storm flap. The finish fabric on the elastic hem and armholes is reflective for a bit of night safety.

The light weight and core warmth provided by the Flash make it a good option for layering and in a sleep system. The same is true for most vests, but does the warmth of the Flash live up to its impressive loft to weight ratio? I took the Flash vest out on a winter hike in Arizona's Aravaipa canyon recently, with low temperatures right at freezing. I was toasty all night in my unzipped bag with the Flash, and I am usually a cold sleeper. I did miss a collar though, and felt noticeably more cool air along my neck and upper chest than I would have with better coverage. The vest would certainly be warmer with a collar, or a higher cut in the neck, but of course there is a weight trade-off. According to Gary Petersen, production manager for Western Mountaineering, the Flash vest has been designed without a collar and with a lower cut zipper to make it easier to layer over the Flash and to reduce clothing and zipper clutter around your neck and upper chest. I did not note any cold spots due to the grid pattern of the down compartments. With a vest this light, I expected that torso coverage might be lacking, but I was pleased with the overall torso coverage. I had plenty of coverage on my long torso and over my shoulders. The cut is plenty roomy enough to allow some layering under the vest. There is no drop tail.

Western Mountaineering Flash Vest REVIEW
The Flash vest provides good coverage for such a light vest - with more than adequate shoulder and torso coverage (left). The reflective tape in the finish is a nice touch as seen in this flash photo (right).

It's obvious that the Flash should be able to pack down to a small size, but I decided to see for myself. The Flash vest does not come with a stuff sack, but I easily stuffed my vest into a stuff sack normally used for a wind shirt. It fit into this sack with plenty of room to spare, and with a little tighter squeeze, it would pack down even smaller. Just like a wind shirt, the small size and light weight eliminate reasons not to carry it. It is a good choice for emergency insulation in case of unexpected cold on short trips. Heck, take a couple of them.

Western Mountaineering Flash Vest REVIEW
Two inches of loft packed into a windshirt stuff. Now that's compact! (Stuff sack not included.)

For the past year, I've been using synthetic vests whenever I carried a vest. How well would the Flash vest hold up if it got really soaked? To find out, I dunked and soaked the Flash vest and am pleased with its ability to recover rapidly from a complete soaking. See the accompanying article on down versus synthetic vests for the complete test results. In light rain the shell fabric has easily repelled water and kept the down dry - but my field testing in this regard has been hampered by a record drought this winter in Arizona. The performance of the shell fabric repelling water is still largely untested. I don't care much for elastic hems - especially if they close up tightly on my hips or waist. The elastic hem on the Flash cinches securely around my torso and has a tendency to ride up on my waist as I move around.

What's Unique

The lightest down vest on the market. Core warmth with 2 inches of double layer loft, and only 4.4 ounces for a size large...and that includes a full zipper. At $125, it's a lot of warmth for your dollar.

Recommendations for Improvement

My only recommendation would be the addition of a light drawcord at the waist, or a looser elastic hem. Either of these changes would make the Flash more comfortable.

The Flash excels just as it was designed - as a layer under other garments. Any additions such as adding a collar or closing up the neck opening might increase the versatility of the Flash, but would add weight. After a winter of use I'm glad to have such a light, warm layer and have come to prefer the cut just as it is.


"Western Mountaineering Flash Vest REVIEW," by Don Wilson. (ISSN 1537-0364)., 2006-05-16 03:00:00-06.