Good ol' Snow
Snow is white and reflective. Meters are easily fooled as was yours in the first shot where the snow appears mostly grey. When shooting snow generally adding +2/3 - 1.3 stops exposure compensation helps. Your snow should almost match the white site background.
There are a ton of online photo sites that are helpful.
|Uplifting Colors by BBrooks|
|Hey! by Flor Tempra|
from Laughing Camera
|Nightshift by Hobbyfotograaf|
from - The Steel Worker - (Full Colours Only + A Border)