Mud tumbled down from surrounding hills onto dozens of homes in Lamenele village shortly after midnight on Adonara island in East Nusa Tenggara province. Rescuers recovered 38 bodies and at least five people were injured, said Lenny Ola, who heads the local disaster agency.

Flash flooding killed at least 17 people elsewhere and at least 42 are missing, according to the National Disaster Mitigation Agency. Relief efforts were hampered by power cuts, blocked roads covered in thick mud and debris as well as the remoteness of the area on an island surrounded by choppy seas and high waves, said the agency''s spokesperson, Raditya Jati.

The bodies of three people were recovered after being swept away by floods in Oyang Bayang village, where 40 houses were also destroyed, Ola said. Hundreds of people fled submerged homes, some of which were carried off by the floodwaters.

In another village, Waiburak, three people were killed and seven missing after overnight rains caused rivers to burst their banks, sending muddy water into large areas of East Flores district, Ola said. Four injured people were being treated at a local health clinic.

The death toll reached 55 by Monday morning after the rains caused cold lava to tumble down the slopes of Ili Lewotolok volcano and hit several villages, Jati said.

That disaster on Lembata island killed at least 11, while at least 16 others were still buried under tons of cold lava, Jati said. The lava was left after the volcano had erupted in November.

Hundreds of people were still involved in the rescue efforts as of late Sunday, Jati told a news conference. At least six villages have been affected by flash floods and a landslide that cut five bridges on the island, he said.

Photos released by the agency showed rescuers and police and military personnel taking residents to shelters.

Authorities were still collecting information about the full scale of casualties and damage in the affected areas, Jati said. Severe flooding also has been reported in Bima, a town in the neighbouring province of West Nusa Tenggara, forcing nearly 10,000 people to flee.

Seasonal rains frequently cause flooding and landslides in Indonesia, an archipelago of 17,000 islands where millions of people live in mountainous areas or near fertile flood plains.