With increased activity coming from Indonesia’s Mount Agung, authorities there have raised the Threat Warning to the highest level possible and expanded the mandatory evacuation zone. Major airports in the area, including Bali’s Ngurah Rai, have suspended operations, trapping tens of thousands of tourists beneath a growing cloud of volcanic ash.
Indonesia’s disaster management agency (BNPB) spokesman, Dr Sutopo Purwo Nugroho, said in a statement that the volcano, which began to spew lava on Saturday, has also continuously ejected ash while the sound of intermittent eruptions can be heard as far as 7 miles away. BNPB issued the level four warning alert, which is the highest possible, at 6am local time. Residents have been told to evacuate from the danger zone, which has been expanded to 6.2 miles out from the earlier 4.5 mile evacuation zone.
A bright glow from the lava on the volcano summit was often seen on Sunday night, signalling that potentially greater eruptions are very imminent, Dr Sutopo said.
Mount Agung is a composite volcano referred to as a stratovolcano. Stratovolcanoes are characterized by a steep profile and their periodic explosive eruptions. Lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity, leading to the construction of your typical triangularly shaped volcano compared to the more rounded, sloped volcanoes seen elsewhere in the world such as Hawaii’s Mauna Loa Volvcano.
Ash carried into the atmosphere can destroy jet aircraft engines and surfaces. Because of that threat, authorities have expanded a no-fly area around the volcano. This area could be further expanded, blocking air travel around southeastern Asia and travel between Asia and Australia.
Beyond the impacts to aviation, the volcano has the potential to disrupt climate and weather around the globe. Past major eruptive events around the world have had significant impacts to weather far away from the volcano itself. After a violent eruption in Indonesia in 1815, winter-like conditions were experienced in the summer in the northeastern United States in 1816. Known as the “year without a summer”, some of the most unusual climatic reports were five consecutive late June nights with frost in Cape May, New Jersey; snow falling on June 7th and 8th in Massachusetts and lake and river ice found in July and August as far south as northwestern Pennsylvania.