Rescue operations are underway in northern India after a devastating flash flood swept through a mountain valley in Uttarakhand State, killing at least four people and leaving parts of a hillside town buried under thick mud.

The disaster, triggered by a sudden cloudburst early Tuesday, struck Dharali, a tourist destination in the Himalayan region, causing a massive mudslide that sent torrents of debris crashing through homes and buildings. A cloudburst is an intense, brief rainfall of rain over a limited region that frequently results in flash floods.

Footage aired on local media showed walls of muddy water engulfing multi-storey apartments as they collapsed into the valley below.

Uttarakhand Chief Minister Pushkar Singh Dhami described the situation as “extremely sad and distressing,” adding that rescue teams had been deployed “on a war footing” to assess the damage and search for survivors. He said he remains in constant contact with emergency personnel and is monitoring the situation closely.

Senior district official Prashant Arya confirmed the deaths and said the toll may rise as teams comb through the debris.

The Indian Army, which has joined search and rescue efforts, said “a massive mudslide struck Dharali, triggering a sudden flow of debris and water through the settlement.”

Images released after the main floodwaters receded show streets submerged in slow-moving sludge, with rooftops barely visible in some places.

A disaster official, who declined to be named, said many residents escaped the worst of the flooding because they were attending a nearby fair at the time.

Prime Minister Narendra Modi extended condolences to victims of what he called a “tragedy,” pledging swift assistance. “No stone is being left unturned in providing help,” he said on social media.

The India Meteorological Department issued a red alert for the area, noting that “extremely heavy” rainfall of up to 21 centimetres had been recorded in isolated spots.

Such disasters are not uncommon during India’s monsoon season from June to September, but experts say climate change and rapid urban development are making flash floods and landslides more frequent and more deadly.

The UN’s World Meteorological Organization has warned that increasingly intense weather events, floods and droughts alike, signal a worsening global water crisis driven by a changing climate.