SHOOT ANY TIME OF DAY
In the winter there is no need to limit yourself to shooting at sunset because the sun will stay much lower in the north and south and the days are often overcast. This makes a large majority of the day a viable option for photography.
CHECK YOUR METERING MODE
Metering is how your camera determines the correct shutter speed and aperture based on the amount of light that goes into the camera. Most DSLRs are automatically set in matrix metering or evaluative metering mode, which divides the camera into zones to determine the correct exposure. In the snow, you don’t want to leave your camera in this mode because it will average the image and expose for grey. Instead, try spot metering the brightest part of the snow.