Image copyright EPA Image caption Homes were destroyed in Managadwa village in Bara district

At least 30 people have been killed and hundreds more injured as a violent thunderstorm swept southern Nepal.

The freak storm destroyed houses, overturned vehicles, uprooted trees and brought down power lines in Bara and Parsa districts, officials said.

The casualties included passengers in a bus that was blown off a road, witnesses said.

Kusum Kalu, 70, told the BBC she had escaped death "by a fraction of a second" when the storm struck.

"I was about to leave the house and just as I opened the door the roof of the house fell down," she told BBC Nepali in Bara district.

"I don't think I would have survived had I already gone to bed or been a fraction of a second late to open the door."

Draupadi Devi, in Balbariyam, Bara, told the BBC that every house in her village had been damaged.

"We were five people at home at that time. A wall crumbled and buried us. We somehow managed to get out of the rubble," she said.

Special forces have been sent to the area to help with rescue and relief operations.

Image caption Many people have been made homeless by the storm

Thunderstorms are common during the Nepalese spring, correspondents say, but are rarely violent enough to cause many casualties.

"I've never seen anything like this. The winds took away everything, my home and my family," said Ram Babu Patel, whose wife died in the storm.

"I was at home getting ready for dinner when the storm hit. It was unbelievable. We have nothing left," he told AFP news agency.

Image copyright Reuters Image caption Hospitals were inundated with patients after the storm

Rescuers in Bara district said emergency aid was desperately needed.

"The storm destroyed everything in its path. Houses have no roofs and trees are all down," volunteer Prakash Tharu said.

Search teams were unable to reach some areas because roads were blocked by fallen trees and other debris. Police warned that the death toll could rise.

Nepalese Prime Minister KP Sharma Oli said the government was doing all it could for the injured.