The Himalayas have no shortage of intimidating and dangerous trails, but the Annapurna circuit in Nepal was not supposed to be one of them. Called the “perfect circle,” the 128-mile, horseshoe-shaped trail attracts thousands of hikers every year. “Fact is, the Annapurna circuit is so well-known it’s as much cliche as trek,” Backpacker wrote in 2009. “Travel writers and hikers everywhere gush about the trail.”

They aren’t gushing right now — and they might not for some time. As of Thursday morning, following an avalanche and blizzard, as many as 29 hikers have been confirmed dead, according to the German news agency DPA. They include Canadians, Israelis, Poles and several Nepalis. And reports now say that number is expected to climb even higher as rescue teams search for 70 missing hikers stranded in one of the most remote areas on Earth, cut off by waist-high snows and weak phone signals.

“The phone network is not very good so we have not been able to get in touch with the missing,” local official Baburam Bhandari told the Sydney Morning Herald. “But we hope to find them later today.”

If that doesn’t happen, it would serve as another blow to a weak Nepalese economy dependent on tourism and still recovering from the April death of 16 Sherpas on Mount Everest. This fresh disaster, however, targets the other sort of hiking in Nepal: the safe routes, the ones people take when they don’t want to put their lives at risk — but nonetheless did.

“Most trekkers on a route like the Annapurna circuit would have no mountaineering experience whatsoever,” Adrian Ballinger, owner and head guide of Alpenglow Expeditions, told National Geographic. “They’d be hikers, maybe without much wilderness experience.”

It’s easier than ever to trek into the Himalayas without any experience as the region becomes more accessible by road and airplane. “Many assume walking into the Himalayas is only for rugged types who enjoy roughing it,” a Guardian travel article said. “That was true in 1953, when Everest was first climbed and trekking tourism didn’t exist…. The walking itself is usually not too difficult, no more so than in the Lake District — apart from the altitude, of course.”

But even on such a trail, the hikers, drawn by clear, cool October air, weren’t safe. At least 12 of them died when they were trapped by a sudden blizzard, the result of a cyclone moving through India a few days ago. The weather lifted somewhat on Wednesday, which allowed rescue teams to spot several bodies.

“Unexpected snow brings unexpected avalanches,” Karl Birkeland of the U.S. Forest Service National Avalanche Center told National Geographic. “Any time you have heavy snowfall with wind-borne snow, you are increasing the odds of avalanches.”

That shatters the myth that any trail in the Himalayas would always be safe. “In a storm condition, all of a sudden you’re in extremely high altitude,” Ballinger said. “It turns into real mountaineering.”

And according to the Associated Press, there could be yet another explanation:

An avalanche in April just above the base camp on Mount Everest killed 16 Nepalese guides, the deadliest single disaster on the mountain. Climate experts say rising global temperatures have contributed to avalanches in the Himalayas.