Now that work isn't so hectic...
If it's a combination of sun AND snow, lowest ISO you can get, and maybe dial in a bit of exposure compensation (+1, 1.5 or 2 range), as all of that brightness is going to wreak havoc on metering. You'll definitely want to shoot RAW so you can draw out the most with your editing. Watch out for over-editing, too, as I've seen some folks that have ended up with oddly colored snow (pink/orange/yellow). Snow, especially in the shadows, tends to carry a bit of a "blue" to it, but that's ok. A "purple haze" isn't though, unless you're going for a Hendrix effect.
A trick I learned is to set my white balance to "FLASH" instead of sunlight, as again... that snow works over your metering and tends to make faces/people look a bit washed out and underexposed.
Another useful tip in extreme lighting situations like that, shoot 3 pics of each pose, if possible, with slightly different exposures. Bracketing, if you've got it, just realize that people sway slightly, so you might not be able to stack 'em for a nice crisp HDR. Even so, it will help you nab (hopefully) at least one well-exposed shot.
Again, GOOD LUCK, let us see the results!