The North Face Thunder Jacket On October 8, 2012 What is it? The North Face Thunder Jacket is packed with 800 fill goose down, weighs in at 400 grams, and features a 20 denier nylon shell exterior. It has two hand warmer pockets and an internal chest pocket. One of the hand pockets doubles as a stuff sack and the entire jacket can be packed down into a ciabbatta bun sized package. Initially, I was a little bit apprehensive about buying a down jacket with concerns about moisture: down loses much of it's insulation value when it gets wet and takes longer to dry out then synthetic insulations such as Primaloft . However, I decided to give it a try as, after I did some research, nothing beats the warmth to weight ratio of a high fill power goose down. What's good? It's warm After a cold Canadian winter's use I can now rightfully say I am a down convert. I've used the Thunder Jacket as a skiing layer and it's kept me toasty warm on my winter backpacking trips . The jacket packs up so small and light that you barely even notice it in your pack, however you definitely do notice and appreciate it when you have it on. Cold mornings require warm coats Putting on a down jacket is like wrapping yourself up in a cozy sleeping bag; it's one of the things I look forward to when stopping for breaks as it keeps all that warmth