Workers offload boxes from a plane carrying Russian humanitarian aid in Sanaa. 

AFP/Sanaa

The UN weather agency warned on Friday that another rare cyclone was heading towards war-ravaged Yemen which would bring more rain to areas already badly battered by cyclone Chapala.

The new storm, named Megh, is brewing in the Arabian Sea and is expected to intensify into "a severe cyclonic storm" over the next 24 hours, with wind speeds of up to 100 kilometres per hour (62 mph), the World Meteorological Organisation (WMO) said.

Megh is not as powerful a Chapala, which killed eight people in southeastern Yemen this week, but is expected to slam into or pass close to the country's already badly hit Arabian Sea island of Socotra on Sunday, WMO spokeswoman Clare Nullis told AFP.

From Socotra, the storm is expected to weaken into a low pressure area as it moves towards mainland Yemen, but will still bring large amounts of rain to areas already devastated by Chapala.

Less intensity

Megh "is not nearly as intense as Chapala. It is not as big. But obviously the rainfall associated with this storm is going to make the problems caused by Chapala... worse, and it will obviously complicate what is already a very complex humanitarian operation," Nullis told reporters in Geneva.

Tropical cyclones are extremely rare over the Arabian peninsula, and having two back-to-back was "an absolutely extraordinary event," she said.

The storms appeared to be caused by high sea surface temperatures and a naturally occurring climate phenomenon resembling the El Nino, called the Indian Ocean Dipole, which allows low pressure systems to move further west over warmer water than is traditionally the case, and develop into cyclones, WMO said.

The UN's humanitarian agency OCHA meanwhile said on Friday that up to 44,000 people had already been displaced by Chapala, which made landfall in mainland Yemen on Tuesday, triggering heavy flash floods and mudslides that killed eight people, two of them children, and injured 34 others.

Key road damaged  

Earlier, Chapala severely hit Socotra, forcing the evacuation of 18,000 people on the island and completely destroying 237 homes, OCHA spokesman Jens Laerke told reporters.

No one on the island was killed, despite initial reports that three people had died, he said.

The coastal road between Aden and the Hadramawt provincial capital Mukalla, which serves as a main transport route for aid supplies, had been damaged by flooding, he said.

Providing relief was also complicated by the fact that some affected areas are held by armed groups, including Al Qaeda.

Getting fresh water in was a top priority, he said, adding that OCHA had set up a special 11-man support and response team, based in Oman, to help with the relief efforts.

More than 900 UN staff are meanwhile already on the ground in Yemen to help respond to the needs after Chapala, but also from the violent conflict plaguing the country.