Mayon Volcano in the Philippines erupted in a massive ash cloud Monday afternoon local time, prompting the threat associated with the deadly volcano to be raised from Level 3 to Level 4 by the Philippine Institute of Volcanology and Seismology (PHIVLOCS). Effectively, that extends the danger zone to a minimum radius of 8 kilometers around the volcano, and it also means a hazardous eruption is possible within the next few days.

The ash column over the volcano was almost 10 kilometers high, and was accompanied by some pyroclastic flow, which contain hot gas and tephra, or fragmented volcanic material. The eruption of steam and ash, as opposed to lava, is called a phreatic eruption.

Mayon Lava Lava flowing from the top of Mayon volcano in Daraga, Albay, Philippines, Jan. 17, 2018. Photo: Jes Aznar/Getty Images

Locals living in nearby areas immediately shared photographs and videos of the eruption on the internet.

The eruption led to the cancellation of classes in the entire province, ordered by the governor.

Earlier in the day and in the intervening night between Sunday and Monday, the volcano was also spewing out lava. Lava was flowing down the mountain slopes in three different flows, two of which formed in the last 24 hours. The longest flow was over 3 kilometers long when PHIVLOCS issued a bulletin at 8 a.m. Monday (7 p.m. EST Sunday). There were two episodes of lava fountaining also through the night.

Mayon is the most active volcano in the Philippines, which, like many other countries in the region, is home to a large number of volcanoes. In the past 40 years or so, about 100 people have been killed due to Mayon’s eruptions, but over 1,000 have died due to indirect consequences from the volcano’s activity.