My guess is that all the porcupines crossed the border and made themselves at home in the Canadian Rockies.
When backpacking in Banff this summer, we had major porcupine issues in the Skoki area. We were forewarned before arriving at camp not to leave anything in our tent vestibule, as the resident porcupines would go right underneath and steal whatever you left out. We also encountered a couple hiking out early, because their poor dog had a snoutful of quills (dogs are allowed in the Banff backcountry, but must stay on leash).
I have to say, they sure do make very cute snuffling sounds when they are active outside your tent at 3:00 am. But I did not enjoy having my muddy boots inside the tent with me.
I did not get the opportunity to photograph one, but you can see their nibblings on these trees.