I'm thinking about a XC ski trip to Yosemite this winter, which would be my first deep snow camping experience. Is a 15 degree bag (not EN rated), ccf pad, REI Minimalist bivy and a tarp enough for Yosemite in winter? Other people I know have 4 season tents for this. I'm thinking that digging a snow trench for the bivy would be the way to go.

There is Yosemite, and then there is the other Yosemite. Some parts, like Yosemite Valley, are somewhat protected, and the snow doesn't get too deep. Little Yosemite Valley is a little higher, but is still somewhat protected. The Glacier Point Road area is higher yet, but less protected. I've snowcamped there (GPR) within the last year, but we got snowed on, so I was a tad bit chilly inside a 4-season tent with a -10 F sleeping bag. Maybe that is just me.

If you wait until the end of March, skiing and camping along the Tioga Road can be quite nice. The road makes a nice navigational corridor so you don't have to worry about getting lost so easily. However, there are some nasty avalanche zones.
--B.G.--

Bob - Do you know the temp range when you got snowed on and chilled?

Actually, glacier point road was exactly what I was looking at. There's a great online map from the park service website I found.

If you were cold in a -10 bag then I would be in trouble...

(This was March 2009). We left Badger Pass with some weather approaching distantly. It must have been about +20 F. We had intended to ski out to Sentinal Dome to camp, but then we thought about the approaching weather and decided to scale down the trip, so we camped around Bridalveil. Before nightfall, it was snowing with wind, and the temperature was maybe +15 F. By morning, it was still snowing a bit and was still +15 F.
There had not been much sleep during the night, because the snow kept sliding off the 4-season tent, and then it piled up to the point where its weight was on the tent wall and on me. We had to keep going out to shovel it away.
A snow shelter might have worked better, but the snow really wasn't deep enough for one until we were leaving.
--B.G.--

"Actually, glacier point road was exactly what I was looking at. There's a great online map from the park service website I found."

The Yosemite Snow Trails map is what you want. Basically, any idiot can travel the Glacier Point Road, and many of them do. All you have to do is to get off the unplowed road and away just a little, and then you have the woods to yourself. There's all kinds of side trails.

Obviously, the scenery gets a lot better out beyond Sentinel Dome. However, you don't have to go that far to have fun. On a good day, you can ski out to Glacier Point and back in about 6 hours.
--B.G.--

Edited by --B.G.-- on 02/08/2010 01:51:28 MST.

I guess the yosemite snow trails map is something you get from the ranger station?

This is the one I've been looking at.

MOST of the time in that area, your 15 degree bag will do the trick - you'll have clothes you can wear to bed if in doubt. Bivy will help a little.
The CCF pad - unless it's a winter-specific pad, like a ridgerest deluxe, you'll probably want 2 pads stacked. The tarp - fine if it doesn't snow and isn't windy, but I would expect it to snow and be windy, so you want something that will block out the wind and blowing snow. Many folks use pyramid style shelters(Megamid,Megalight, Betamid & lite, MLD duomid and supermid, OWARE pyramid, Golite hex, etc) in the Sierra in winter with good success.
Snow trench and tarp can work, if the snow consistency is amenable, and if you have a way to close off the end of the trench to keep out the blowing snow - another small tarp could do that if you rig it right.

Yes, that is the most useful map for where you are most likely to camp. There are other good parts of the park that are reachable in winter.

If you are on skis, the best place to go is Tuolumne Meadows, and the best time is about March 15-April 1. Unfortunately, that is a long haul for skiers, and it is a very long haul for snowshoers.
--B.G.--