Lake Kanas, in China’s Xinjiang province, is about as far from the east coast megacities as it’s possible to get without leaving the country. Sapphire waters flow through pine forests under mountains still capped with snow in June – it’s reminiscent of British Columbia. But now, in lands traditionally home to yurt-dwelling nomads, log cabins are being erected to house busloads of tourists. And where British Columbia has its Bigfoot sightings, Kanas is also home to mythical monsters: lake dwellers a bit like Chinese Nessies.

In the local language, Tuvan, these monsters are called hobzhk, which means “changing” or “strange”. Tuvan lore says they plug the bottom of the 189-metre-deep lake, preventing it from emptying out, a job so important that, 800 years ago, Genghis Khan assigned 126 soldiers to protect them. Grainy video footage aired on Xinjiang TV a few years ago showed huge black creatures breaking the lake’s surface.

The lake has a sapphire hue. Photograph: Yuanping/Getty Images

Xiao Yue, a 20-year-old tour guide, says: “Technically, the hobzhk are huge fish that love to eat meat. Their scientific name is hucho taimen.”

On hot summer days, Yue begs visitors not to swim in the tempting lake, adamant that the creatures have a taste for human flesh. “Farmers take their cows and sheep to the edge of the lake, and they vanish,” she says. “Later they find their bones on the shore.”

Swimming is prohibited in the lake, but that has more to do with concealed rocks and a swift current. The more immediate anxiety is civil unrest. In 2014, tourism in Kanas plummeted after blasts in Luntai, 600km to the south, killed 50 people, as tension mounted between the ethnic Han majority and the Uighur Muslims.

The waters look serene but, according to myth, are home to large meat-eating fish. Photograph: VuCongDanh/Getty Images

To assuage anxieties stoked by the state press, metal detectors are ubiquitous, as are helmeted security guards. Kanas itself hasn’t experienced significant violence, though, and Yue is adamant the area is safe. The heightened security comes courtesy of Chen Quanguo, the new party chief of Xinjiang, who has set up a network of prefab police stations all over Xinjiang.

By 2015, however, tourism had recovered. Visits to the Kanas Scenic Area rose by 6% to more than 400,000. And in June this year, still low season in Kanas, hotels were already full, a promising sign for several more still under construction in villages such as Hom. Events are being developed, too, with a 100km ultra-marathon trail race and an X-games style snowboard competition now catering to more intrepid tourists, willing to explore one of the most beautiful, least touched parts of China.

The area’s villages, such as Hemu, are traditional and largely untouched by tourism. Photograph: Alamy

Locals have found jobs as rafting guides, dancers, throat-singers and “model families” – who serve lamb kebabs, air-dried cheese and “hand-grabbed-rice” (with vegetables and lamb fat) to visitors in their homes.

The security measures must seem strange to nomadic people who never had much use even for fences; they simply tie three hooves loosely together to stop their horses from straying. With the monsters confined to the lake and the Chinese tourists fenced into their log cabin complexes, much of Kanas remains wild and free, with plenty of landscape left to explore.

As to the security threat, Yue puts it best: “There’s a prejudice elsewhere against Xinjiang people. But we are great – really warm and friendly. You haven’t felt unsafe, right?”

• More information from chinahighlights.com/kanas

Additional reporting by Wang Lin