This type of scene has too great of a contrast range to get both the highlights and darker subject all exposed acceptably. Changing the ISO won't do anything but change what shutter speed and aperture the camera or you deem correct. The brightness range is still the same. You can expose the bright areas correctly but that leaves the subject underexposed. If you expose the subject correctly, the background is overexposed. In other words, there are no camera settings to reduce this brightness range and get it all exposed acceptably.
Graduated neutral density filters are used for scenes such as sunsets where you want to reduce the contrast range between the sky and foreground.
I use the Shadows/Highlights tool in CS6. You can always brighten the dark areas and darken the highlights but never recover the blown highlights. It also does a great job of creating simple HDR photos from one photo.
This was taken during Snow storm using a 18-55mm Kit lens D3200 The picture looks exactly like what I was seeing as I took the picture. I suppose I have run the speed up some way to freeze frame snow Flakes. But I like this affect/effect (never have gotten down the correct usuage).
What type of metering are you using? I use centre weighted metering when in snow. I dont use matrix metering under those circumstances at all. Also EV -0.7 exposure compensation usually. Bracketing (as suggested above) is also a good suggestion.
Snow scenes usually have a large dynamic range to them. The newer cameras help with their expanded range sensors, but even then the difference between the highlights and the shadows are still too big for the sensors.
The light meters tend to want to average the scene to a medium gray. The newer cameras are better at handling the snow, but still not perfect. Shooting raw instead of JPG is a big help.
What to do depends on the type of picture you are looking for. If you want a landscape shot, you could go with the metered shot or maybe dial in a little negative EV so that you maintain the detail in the snow and fix the exposure in post processing.
If you are looking for a people shot (skiers, snowshoers, etc.) then you will want to overexpose the snow to get the people exposed correctly using a goodly amount of +EV.
Unfortunately, without going into HDR processing, getting both in the same shot is not possible.
---------+---------+---------+---------+---------+ Joseph K Seattle, WA, USA