When shooting scenes like this, you’ll need to use exposure compensation in order to get white snow. In both of these images, I used +1.3 stops. Shooting at the metered setting will likely give you dingy grey snow since the meter is overwhelmed by all of the white in the scene.

As an alternative, you can meter off of another object. In the water pump, metering on the red pump yielded nearly the same exposure value as I got by using exposure compensation when metering off the snow. To do this, you’ll need to have an exposure lock feature that will let you recompose the image after metering. This is often called AEL.