JAKARTA — The death toll from catastrophic flooding and landslides on Indonesia’s Sumatra island has surged to 417, officials said on Sunday, as monsoon rains intensified by rare tropical storms continue to devastate large parts of Southeast Asia.

Evacuation operations remain under way, with major roads cut off and power and internet services only partially restored across affected areas. Authorities warn hundreds more remain missing.

The region has been hit by some of the worst flooding in years, with deadly impacts stretching across Malaysia, Thailand and Sri Lanka.

In Thailand, at least 170 people have died, while Malaysia’s northern Perlis state has reported two deaths.

Sri Lanka has recorded nearly 160 fatalities following severe rains, flooding and mudslides triggered by Cyclone Ditwah.

Indonesia has suffered the heaviest losses. Cyclone Senyar — an exceptionally rare storm forming in the Malacca Strait — unleashed massive landslides and flash floods that swept away homes and submerged thousands of buildings. Residents in Aceh and West Sumatra described torrents strong enough to swallow entire structures within seconds.

“The current was very fast… it reached the streets and entered the houses,” Aceh resident Arini Amalia told the BBC. Others recounted clinging to trees and clotheslines as floodwaters surged through their homes.

Rescue efforts remain hampered by ongoing bad weather, with hundreds still stranded and tens of thousands displaced.

In Tapanuli, one of the hardest-hit districts, residents have reportedly broken into shops in search of food, prompting calls for Jakarta to declare a national disaster to accelerate the emergency response.

Across southern Thailand, where waters rose up to 3 meters in Songkhla province, more than 3.8 million people have been affected.

Hat Yai recorded its heaviest daily rainfall in 300 years, overwhelming hospitals and forcing morgue staff to store bodies in refrigerated trucks.

In Malaysia, swaths of Perlis remain underwater, with tens of thousands taking refuge in temporary shelters.

Sri Lanka has declared a state of emergency as Cyclone Ditwah battered the country, leaving 193 people dead and more than 200 missing. A third of the nation remains without electricity or water.

Meteorologists say the extreme weather may have been intensified by the interaction of Typhoon Koto — now moving toward Vietnam — and Cyclone Senyar. Vietnam has already reported three deaths linked to the approaching storm.

Scientists warn that climate change is making severe storms, heavy rainfall and flash flooding more frequent and more intense across the region. — Agencies