Indonesian authorities evacuated 100,000 people in the island of Bali and shut its airport after Mount Agung volcano erupted, prompting airlines to cancel about 445 flights linking one of the most popular tourist destinations in Asia.
Relocation from around Mount Agung’s crater began as volcanologists warned of a “very high likelihood” for a larger eruption, the National Disaster Mitigation Agency said in a statement Monday. The volcano expelled ash clouds as high as 4 kilometers (2.5 miles) above the crater and residents as far as 12 kilometers away reported low explosive noises and flares.
Videos released by the National Disaster Mitigation Agency showed a mudflow of volcanic debris and water known as a lahar moving down the volcano's slopes. It said lahars could increase because it is rainy season and warned people to stay away from rivers.
The agency raised the volcano's alert to the highest level early Monday and expanded the danger zone to 6 miles in places from the previous 7 1/2 kilometers. It said a larger eruption is possible.
Bali's airport was closed early Monday after ash, which can pose a deadly threat to aircraft, reached its airspace. Flight information boards showed rows of cancellations as tourists arrived at the busy airport expecting to catch flights home.
Active volcanoes can throw ash miles into the air. Even though, volcanic ash may seem relatively harmless from the ground, when aircraft collide with it at hundreds of miles per hour it’s an entirely different story.
Ash is heavy enough to make it incredibly hard to see out of a cockpit window. This is an expected condition of flying near an active volcano, but pilots are trained to fly in situations with little to no visibility with help from radars. Even so, flying into a giant column of ash is not something pilots do on purpose.