Mount Agung erupted on November 21 at 17.05 local time, announced the Center for Volcanology and Geological Hazard Mitigation.

This comes barely a month after the volcano alert level was lowered from ‘dangerous’ to ‘high alert’. Despite the eruption – which saw thick grey smoke rising to a maximum height of about 700m above the peak – the status remains on alert level three.

The disaster management agency said the eruption was small so far, with volcanic ashes blowing to the east and southeast, and urged locals to not panic and pay attention to the official recommendations and instructions.

“A phreatic eruption can be a stand-alone eruption, but can also be a preliminary eruption before a series of magmatic eruption,” Sutopo Purwo Nugroho, head of central data information and public relations of the National Disaster Mitigation Agency (BNPB), said.

The eruption at Mount Agung, a phreatic eruption, was caused by heavy-pressure vapour formed by the heating of the water underground, or rain water absorbed into the crater soil and coming into direct contact with the magma, Sutopo explained.

It is currently rainy season in Bali.

Meanwhile, the Bali Tourism Board (BTB) Mount Agung Task Force urges the public to monitor official sources, such as the Bali Tourism Board, PVMBG and MAGMA Indonesia, and “not be influenced by dramatic hoax reports emanating from the social network and a number of foreign news agency”.

Three to four hours after the eruption, flights to and from Bali’s Ngurah Rai Airport, located more than 60km south of the volcano, were operating largely to schedule with no indication of flight delays or cancellations linked to the eruption, it pointed out.

The World Organization of Volcanic Observatories (WOVO) has an ‘orange’ warning in place for Mount Agung, a rating used by aviators. ‘Orange’ is the second highest alert level indicating the volcano is exhibiting an increased likelihood of an eruption but with little or no volcanic ash being emitted into the atmosphere, it said.

Estimates at sunset on Tuesday put the ash-cloud top at around 3,842m above sea level, warning the height might be more than can be easily observed. The current ash cloud is moving to the east-southeast of the volcano.