The death toll from flash floods in a northern Afghan province has hit 50 -- most of them women and children -- an official said on Saturday, a week after the disaster struck.

The floods that inundated Sari Pul province were triggered by torrential rain and have left thousands of people homeless, provincial governor Abdul Jabar Haqbeen told AFP.

"The floods have killed 50 people so far, mostly women and children," he said.

"Around 59,000 people have been displaced, and dozens are still missing," he said, adding that around 260 villages had been affected.

Rescue teams have launched an operation to find the missing people, he said.

Afghanistan's harshest winter in 15 years saw unusually heavy snowfalls and experts predicted that rivers swollen by melting snow were likely to flood in the mountainous north in spring.

According to IMMAP, a data-analysis and mapping company, 15 percent of Afghanistan's population is at high risk of being affected.

In March, the UN humanitarian office for Afghanistan said at least 145 people were missing and "presumed dead" after an avalanche hit a remote village in northeastern Badakhshan province.