[Cdt-l] reservations in Glacier

[Jo Pegrum Hazelett]

I understand that you cannot make a reservation at Fifty Mountain (15.8
miles in from the start of the trail at Waterton Lake)  until August (that's
what a ranger told me). In addition, it appears I am really late making
reservations at any of the sites in Glacier National Park. Can anyone tell
me how difficult it is to show up and try for an on site reservation
(apparently 50% of them are made that way)?

We are coming from California and have limited time so we cannot afford to
wait too long for things to open up once there. Does anyone have any advice
on this?

Thanks
Jo