So the lion comes in with the beginning of March … but what if it decides to hang around a while?  If the whole “out like a lamb” part hasn’t really happened yet, at least you can benefit from having some merino sheep on your side.

Icebreaker Blast LS Jacket Features:

  • Lining: 100% merino wool
  • Middle layer: 100% polyurethane membrane
  • Soft shell outer surfaces: 100% polyester
  • Side and back panels: 39% merino, 45% nylon, 16% elastane
  • Adjustable drop-tail hem
  • Dual hand zippered pockets
  • Vertical zippered chest pocket
  • Thin, large back ventilation panel
  • Media cord pass-through slot
  • Three color options
  • MSRP $249

Icebreaker Blast jacket running

The Blast LS experience

Icebreaker established itself in the performance apparel industry with its predominant use of old-school merino wool, but this spring the company is fusing natural materials with high-tech elements to create weather-resistant outerwear that is suitable for unpredictable and occasionally harsh spring or fall conditions.  The Blast jacket and vest are midweight garments intended to be used for either running or cycling.


With any Icebreaker products, you know you’re getting well-constructed gear that stands up to repeated thrashings and washings, and merino wool is famous for its odor resistance; both of those qualities are on display with the Blast.  It’s a best-case scenario: you could wash it if you want to, but there’s rarely a need to do so.  Part of my testing consisted of several consecutive runs without washing, and there wasn’t any funk – whether hanging on my body or in my closet.

Weather resistance is very strong, with outer panels that protect against wind and rain for long enough to finish your 10-miler.  Then again, if you want to stretch it to 20, you’re covered there as well, as merino wool is highly effective at maintaining insulation even when wet.  One drawback is that the three layers of protective paneling combine to feel rather thick, and they add noticeable weight to the garment.  If Icebreaker could shave a little bit of bulk and weight on future versions of the Blast, that would be a great upgrade.

Icebreaker blast jacket back panels

Back view: weather resistant panels on top, thin stretch merino layer below

The protective panels don’t breathe remarkably well, which is partially compensated by large back and side panels made of thin breathable wool, nylon, and elastene.  These thinner fabrics have nice stretch properties as well, so the Blast jacket doesn’t impede your range of motion when running hard.  The thin layers aren’t quite enough to offset the heat retention in the weather-resistant panels, so the Blast tends to run warmer (and insulate better) than similar midweight shells.

Cut of the jacket is straight through the trunk, and the dual-color styling with understated zipper seams is fairly subtle (except perhaps for the blue color option), making the Blast a good option for post-workout casual wear, especially since it won’t retain any odor.  The straight cut continues into the neck area, which I found too constricting at full zip.  One other fit-related point: although the jacket is billed as a combination run/bike jacket, the sleeve length and waist length ride a bit too short for most folks to be leaning toward the handlebars.

The Good:

  • Outstanding odor resistance
  • Excellent wind and water resistance with polyester panels
  • Maintains insulation even when soaked

The Bad:

  • Narrow neck collar
  • Sleeves and waistline too short for cycling

The Bottom Line

Built for the harsher side of spring or fall, Icebreaker’s Blast jacket provides great insulation and water resistance in inclement conditions, but is better suited for running than cycling.

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About Author

Donald is a physical therapist, ultrarunner, barefoot aficionado, and father of three with more than 20 years of experience in endurance sports. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.

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