The Himalayan hiking circuit where at least 23 climbers were killed in a blizzard and avalanches this week is less than 200 miles from Mount Everest. But its trails appeal to a whole different type of adventurer.

Whereas Everest, the world's tallest mountain, attracts the world's most accomplished alpine climbers, Nepal's Annapurna circuit, the site of Tuesday's disaster, is among the Himalaya's most popular treks for casual hikers. It's been dubbed the "world's greatest trek."

But the 150-mile (241 kilometer) circuit turned deadly on Wednesday, and those who know the area say the inexperienced climbers who frequent the route were likely unprepared to contend with extreme weather conditions. Many people are still missing, with dozens feared dead, as helicopters rescued hikers