THE Ktunaxa First Nation, an indigenous group in south-eastern British Columbia, believes that the grizzly-bear spirit resides in a sacred part of the Purcell mountains that they call Qat’muk. For 25 years they have resisted a scheme to build a ski resort in this wilderness. On December 1st the Ktunaxa will bring their fight to Canada’s Supreme Court. They will argue that their religious freedom takes precedence over the right of mountain-bombing masses to experience the deep powder for which the area is famed.

The case will set a precedent in Canada and reverberate abroad. Sacred sites are an issue in protests against the Dakota oil pipeline in the United States. New Zealand’s government recently conferred the rights of a person on a national park sacred to the Maori people. Canada’s Supreme Court has ruled before on indigenous people’s rights over land use, but never on the basis of their religious beliefs.

The nature of that faith, which assigns sacred value to features of the landscape, poses a puzzle for the courts. The Ktunaxa maintain that skiers will drive away the grizzly-bear spirit, making their rituals meaningless. Canada’s Supreme Court must now decide whether that danger represents an infringement of the religious freedom established by the constitution, and whether that infringement is justified.

The Ktunaxa lost the first two rounds of legal tussling. Lawyers for Glacier Resorts, which is developing the project, say the Ktunaxa informed them only in 2009 that the site was sacred. They point out that the Shuswap First Nation, which settled near the sacred area in the 1850s, supports the resort, which will bring employment. British Columbia’s appeals court rejected the argument that the Ktunaxa do not hold their beliefs very strongly. But, it ruled, their faith may not restrict use of land by people who do not share it.

The appeal to the Supreme Court has prompted 14 outside groups to file friend-of-the-court briefs. Religious organisations, such as the Muslim Lawyers Association, argue for a broad interpretation of religious rights. The Chamber of Commerce wants a narrow one.

Such groups worry that a decision in favour of the Ktunaxa will set off an avalanche of similar claims. There might be thousands of sacred sites in Canada. These fears are exaggerated, says Michael Lee Ross, a lawyer in Vancouver who has written a book on sacred sites and the courts. The Supreme Court is accustomed to setting limits on the rights guaranteed by the constitution, he says. Whatever its decision on the grizzly-bear spirit, skiers will find new mountains to conquer.