Rescue operations were severely hindered Friday after flash floods and landslides on Sumatra Island killed at least 79 people and left dozens missing, with damaged roads, bridges, and limited heavy equipment slowing relief efforts.

Tropical Cyclone Senyar, forming in the Strait of Malacca, has driven heavy rains and strong winds across North Sumatra, West Sumatra, and Aceh provinces. Monsoon downpours caused rivers to overflow, sweeping away mountainside villages and submerging thousands of homes. In North Sumatra alone, more than 3,200 houses were flooded, and around 3,000 families were displaced to government shelters.

Authorities reported 48 dead and 88 missing in 12 cities and districts of North Sumatra, where mudslides, power outages, and disrupted communications made reaching victims difficult. West Sumatra province saw at least 22 deaths and 10 missing, with more than 17,000 homes submerged and tens of thousands evacuated. Rice fields, livestock, and public infrastructure were also damaged.

In Aceh, mud and rocks blocked roads, delaying the transport of excavators and other heavy machinery. Three villages in Central Aceh district reported nine fatalities and two missing residents.

Officials warned that continued heavy rainfall and unstable atmospheric conditions could prolong extreme weather. “We have extended its extreme weather warning due to strong water vapor supply and shifting atmospheric dynamics,” said Achadi Subarkah Raharjo, Director of Aviation Meteorology at Indonesia’s Meteorology, Climatology, and Geophysical Agency.

Seasonal rains frequently trigger floods and landslides in Indonesia, an archipelago of 17,000 islands where millions live in mountainous regions or flood-prone plains. Authorities continue urgent search and rescue efforts as communities assess the widespread damage and cope with the human toll.