Jefferson is the pole of inaccessibility in winter. With the closure of Jefferson Notch Road, there are no easy ways up this mountain. Described below are a few options for approach and my personal recommendations. For Jefferson Ravine, the fastest way to access is most definitely to skin the Cog or Jewell Trail and tag Mount Clay. In general I’ve found it worthwhile to hike over the summit of Clay rather than bypassing it to the west side, the side hilling on talus is way more annoying than 100 extra feet of elevation gain. Usually a short snowfield can be skied from the summit of Clay down to Sphinx Col. From here, gentle ridge hiking following Gulfside Path leads to a shoulder where you can access The Beach. Skiing The Beach into Stealth Gully is an excellent run, and the fastest way into Jefferson Ravine. If your objective is Jefferson Headwall, it probably makes more sense from a “ski positive” perspective to ski Beach/Stealth, then climb Jefferson Headwall from below, than it does to hike up and over Jefferson. For Castle Ravine, the fastest way to get there is to summit Mount Jefferson, then hike down Castle Trail to the top of the gullies. It’s a chore to get in and out of Castle this way, making skinning in via Castle Ravine trail look more appealing on paper. I haven’t gone in this way, but everyone I’ve heard about doing it this way seems to have regretted it. Another “ski positive” alternative is to ski Beach/Stealth, climb Jefferson Headwall, and top out at Edmands Col, then cross directly into Castle. It’s a huge day, but makes the hike/ski ratio a little more justifiable. For the best exit to Castle, trust me, hike up and over Jefferson. Trying to circumnavigate Jefferson via Cornice Trail was not the move. Be aware that this is big, remote terrain, all without realistic exits out the bottom. You likely won’t see any other parties out here. Skiers must be self reliant in the event a situation arises.