PESHAWAR, Pakistan — Flash floods triggered by torrential rains have killed over 280 people in India and Pakistan and left scores of others missing, officials said Friday, as rescuers brought to safety some 1,600 people from two mountainous districts in the neighboring countries.

In Pakistan, a helicopter carrying relief supplies to the flood-hit northwestern Bajaur region crashed due to bad weather, killing all five people on board, including two pilots, a government statement said.

And devastating floods in India led to the suspension of an annual Hindu pilgrimage and the evacuation of thousands of pilgrims.

Cloudbursts — sudden, intense downpours over small areas — are increasingly common in India’s Himalayan regions and Pakistan’s northern areas, and can wreak havoc by causing inten

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