Heavy rain over an erupting volcano in the eastern Philippines is threatening to trigger deadly mudflows as debris and sediment deposited on its slopes are washed out.
Mayon Volcano in Albay province, 330 kilometres south of Manila, has been belching out ash and lava since January 13, forcing nearly 67,000 people to evacuate their homes at the foot of the mountain.
The eruption has deposited millions of cubic metres of thick pyroclastic materials and ash fall on watershed areas and slopes of Mayon Volcano, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).
"These deposits can be remobilised by rainwater and generate lahars (mud flows) by themselves and or by incorporating existing erodible (sic) material on channel banks," Phivolcs warned in an advisory on Saturday.
The institute has already monitored "some signals" of mud flows from Mayon following heavy rains overnight, Mariton Bornas, chief of the institute's volcano monitoring and eruption prediction division said.
"We have fresh deposits on the slope and with the rain, it's really a dangerous combination for the communities," she said.
"Lahar from Mayon can carry huge boulders," she added.
"It's very dangerous not only because it can bury communities, wash away people and everything in its path, but also because of impact."
Bornas noted that the last major disaster related to Mayon was in 2006, when a typhoon battered the province after the volcano erupted, triggering mudflows that killed 1,300 people.
About an equal number of people were missing and presumed dead.
"It's a real threat so we are urging everyone to prepare and evacuate when told by authorities," she said.
The 2,463-metre volcano has erupted about 50 times since 1616.
The last deadly eruption was in May 2013 when five hikers were killed and seven people injured.
