Flash flood washes out Himalayan town, killing four

Rescue teams were deployed on Tuesday to India's Himalayan region after flash floods tore down a mountain valley, appearing to wipe away much of a town, where at least four people were killed.

Videos broadcast on Indian media showed a surge of muddy water sweeping away multi-storey apartment blocks in the tourist region of Dharali in Uttarakhand state.

Uttarakhand State Chief Minister Pushkar Singh Dhami said rescue teams had been deployed "on a war footing". Senior local official Prashant Arya said four people had been killed, with other officials warning that the number could rise.

"Luckily, most of the people were at a fair in a safe location," said a disaster official who asked not to be named since he was not authorised to speak to the media.

India's army said its teams had reached the town.

"A massive mudslide struck Dharali... triggering a sudden flow of debris and water through the settlement," it said.

Images released by the army, taken from the site after the main torrent of water had gone, showed a river of slow-moving mud.

A wide swathe of the town was swamped by deep debris. In places, the mud lapped at the rooftops of houses.

Prime Minister Narendra Modi expressed condolences to those "affected by this tragedy".

"No stone is being left unturned in providing assistance to the people," he said in a statement posted on social media.

Chief Minister Dhami said the flood was caused by a sudden and intense downpour.

"News of heavy damage caused by a cloudburst... is extremely sad and distressing," he said.

"I am in constant contact with senior officials, and the situation is being closely monitored," Dhami added in a statement.

The India Meteorological Department issued a red alert warning for the area, and recorded "extremely heavy" rainfall of around 21 centimetres (eight inches) in isolated parts of Uttarakhand.

Deadly floods and landslides are common during the monsoon season from June to September, but experts say climate change, coupled with urbanisation, is increasing their frequency and severity.

The UN's World Meteorological Organisation said last year that increasingly intense floods and droughts are a "distress signal" of what is to come as climate change makes the planet's water cycle ever more unpredictable.