In the wake of Saturday’s devastating 7.8 magnitude earthquake in Nepal, weather conditions have had a major impact on the huge rescue and recovery operation.

As the official death toll rose beyond 5,000 on Wednesday, many towns and villages remained cut off, awaiting relief supplies.

With so many roads destroyed by the earthquake, or blocked by rubble, these supplies will have to be dropped by helicopters. Unfortunately, flights will be curtailed by factors such as low cloud and poor visibility.

Millions of people have been affected by the largest tremor to hit the region in 80 years, Many of these people have lost their homes, or are too frightened to return because of the risk of aftershocks.

They face the prospect of living under canvas in the coming weeks, or even months, so weather conditions will be critically important to them.

Fortunately, the weather at this time of the year is usually good - hence the large number of climbers in the region when the earthquake struck.

Low rainfall before monsoon

Ahead of the summer monsoon, rainfall amounts are relatively low. The capital, Kathmandu, receives an average of 58mm in April, rising to 122mm in May.

Inevitably, once the monsoon sets in, the valleys and Himalayan foothills become very wet. During the summer months, rainfall totals are in excess of 300mm.

For those still living under canvas, life could become very difficult with the risk of flash flooding adding to the underlying risk of landslides which has increased considerably since the earthquake and its aftershocks.

A small crumb of comfort is that, at least at lower levels, it should be relatively warm. Daytime temperatures, on average, rise to well over 25C from late April right through until October.

Night time minimum temperatures are between 15C and 20C, but it is important to remember that these figures relate to the foothills. Temperatures generally decrease at a rate of 1C for every 100m in altitude. Some of the settlements in the mountains will still be experiencing very low temperatures.

In the immediate future, heavy showers and thunderstorms, which have been affecting central and eastern parts of Nepal, are expected to die out towards the end of the week.

There should then be a period of five days when weather conditions are generally fine, before the threat of showers returns.

Source: Al Jazeera