What Our Gearhead(R) Experts Are Saying: "This is the layer I trust when I'm moving hard in cold conditions. The Polartec Alpha breathes incredibly well, so I don't overheat on the climb, and it still keeps me warm when I stop. It fits cleanly under a harness and packs down small when I don't need it." We reach for the Alpine Start Insulated Hoodie when our days in the mountains demand constant movement and reliable warmth. Black Diamond designed this jacket to thrive in high-output environments, from skin tracks and boot packs to cold belays and windy ridgelines. It's light, packable, and always ready for the next push upward. Polartec Alpha insulation strikes the perfect balance between warmth and breathability, trapping heat without causing excess buildup as our effort increases. A durable, DWR-treated nylon shell stands up to brushes with rock and rope, while the helmet-compatible hood and bound cuffs and hem keep everything secure and dialed. With a drop hem for harness compatibility and a packable chest pocket that stays accessible, this hoodie is built for committed days where adaptability matters most.