I recently used this bag for a MT Washington Summit. I thought it did a great job, the top opening kept the snow out of the main compartment, the crampon pouch was a handy addition along with the ice tool strapping. I did notice however that the water bottle pockets tended to fill up with snow once the weather got pretty bad. In fairness i did have a water bottle and a dry bag in each pocket so they were propped open. Nothing major but perhaps in heavy snow it might be wise to not use the side pockets.