The Park is a different world in winter.
Skiing and snowshoeing are available. This year it is pretty much do-it-yourself, though rentals are available.
Izaac Walton Inn is near Marias Pass on Rte 2. It offers groomed trails and, per its website, equipment rental.
In the past, pre-COVID, the Inn offered lessons, and some years there was a special event, a skiing weekend with bells and whistles, in February.
At Marias Pass, one can xc ski or snowshoe Autumn Creek Trail and connecting trails.
Glacier Guides is not offering guided backcountry ski trips this year but does have a page with some suggested routes and rental places:
https://glacierguides.com/plan-my-trip- ... r-edition/
For fast company, try Glacier Mountaineering Society.
(I do not find ranger-led snowshoe walks of an hour or so at Apgar, as in past years.)