Jakarta, May 15 (IANS/DPA) The death toll from floods and cold lava mudflows in Indonesia's West Sumatra province has climbed to 58, the country's disaster management agency said on Wednesday.

Intense monsoon rains triggered flash floods across several regions of West Sumatra over the weekend, as cold lava and mudflows from Mount Marapi surged down slopes and inundated communities, officials said.

Thirty-five people are still missing, 33 have been injured, and more than 1,500 families have been affected, according to the agency.

Cold lava floods, also known as lahars, are volcanic mudflows that can occur during or after eruptions when heavy rainfall mobilises loose volcanic material.

Lieutenant General Suharyanto, the head of the disaster agency, said the government was prioritising efforts to restore roads and bridges that were damaged or destroyed in the disaster, which has hampered rescue and relief operations.

Helicopters were being used to deliver aid to some areas while authorities were also considering relocating residents whose homes were damaged or destroyed, he said.

He said the country's weather agency would soon launch weather modification operations to reduce rainfall in the area.

"We don't want the efforts in this emergency response phase to be hampered again by rain and bad weather causing further disasters," Suharyanto said in a statement.

Indonesia is prone to natural disasters due to its location on the Pacific "Ring of Fire," an arc of volcanoes and fault lines where earthquakes and volcanic eruptions are common.