Mount Ontake, a volcano that spontaneously erupted in Japan on Saturday, has left dozens of hikers presumed dead near its peak, a spokesperson for the Japanese police said. The mountain continues to spew dangerous smoke, making rescue efforts difficult.

At around 12 p.m. local time today, Japan's Mount Ontake erupted, trapping some 150 climbers on the volcano, the BBC reports. One of those caught in the disaster was YouTube user Kuroda Terutoshi, who uploaded this video showing the eruption's enormous ash cloud overtaking the hiker and his party.