By Saeed Shah, Rajendra Jadhav and Shilpa JamkhandikarISLAMABAD/NEW DELHI (Reuters) -Massive, sudden downpours of rain known as cloudbursts have struck Pakistan and India during this monsoon season, killing hundreds of people in the flash floods and landslides they have triggered.

Across Pakistan, monsoon rains that began in late June have been heavier than usual, killing at least 645 people. Four hundred of those deaths were in the northwest alone, where narrow valleys and river-carved gorges funnel rainwater into sudden torrents.

Monsoon rain in northern Pakistan has caused flooding and landslides that have swept away entire villages, with around 200 people still missing.

SWABI: A powerful cloudburst followed by landslides struck Swabi district in Khyber Pakhtunkhwa on Monday, causing widespread destruction. Homes were swept away and many residents displaced, according to local officials.

Pakistani rescuers dug homes out from under massive boulders on Sunday as they searched for survivors of flash floods that killed at least 344 people, with more than 150 still missing.