“The Nepal disaster is devastating, and for me also very personal.

My home village, Siddhalek, lies on the northern side of the Trishuli River and the surrounding area has been badly affected,

Several bridges connecting our side of the river to the highway on the opposite side have been destroyed. These bridges were not simply pieces of infrastructure; they connected communities to schools, markets, services and the rest of the country.

Students travel across the river to attend school, so when these bridges disappear, the impact continues long after the floodwater recedes. You don't just lose a bridge; you lose part of the everyday connection between communities.

Satellite imagery, remote sensing and other Earth-observation data will help determine what happened.

From an engineering perspective, the important lesson is that we cannot continue looking at climate change, earthquakes, landslides and floods independently,

Nature does not separate these hazards: one event can trigger another and create a much larger cascading disaster.

This is particularly important as the Himalayan environment changes with a warming climate, retreating glaciers and evolving glacial lakes,

Nepal needs better multi-hazard mapping, monitoring and early-warning systems, stronger land-use planning and infrastructure designed with these changing hazards in mind.

Communities also need to know what warnings mean and how to respond. Nepal needs development, but if we rebuild without understanding why this event became so destructive, we risk rebuilding the same vulnerabilities.

The goal should not simply be to rebuild what was lost, but to rebuild safer and more resilient communities.”

"This is a very unique disaster, in terms of intensity and speed, which had a distinct blueprint of impact on communities, and activities around immediate response and recovery. The reports suggest the flood and landslide were caused by a buildup of water in the glacier, which was triggered by seismic activity.

This unique event may trigger the implementation of future warning systems, which is feasible with current state-of-the-art technology. At least the buildup of water can be an early warning sign for downstream communities, a form of seasonal warning for preparation. Such communications and preparations can save lives and reduce the impact at scale.

With global warming, there is an expectation that similar patterns of disasters will recur. We can benefit from the implementation of a warning system, similar to those triggered for tsunami warnings after 2004's tsunami.

The long-term recovery can focus on connecting communities isolated by this disaster. In essence, the priority is to provide baseline infrastructure and connections, so the close-knit communities Soniya mentioned can self-organise their response.”

"The disaster has impacted three districts: Rasuwa (the epicenter of the disaster) on the Nepal-Tibet border, Nuwakot (located southwest of Kathmandu), and Dhading. All are heavily residential. Rasuwa is a popular trekking spot and international trading hub with a large local community.

Bridges connecting the trade routes from China to Kathmandu have been destroyed, including the highways severely limiting the flow of goods and services to the impacted areas. Roads have been destroyed so helping local communities will be difficult. Helicopters have been deployed by the Nepalese government to help those who are stranded. We can’t really see at this early stage how many people have been impacted; it’s possible the impact could be even more devastating than the 7.5 magnitude earthquake that struck Nepal in 2015.

I’ve heard people were notifying neighbours to leave before the flooding hit but, because there was no rain leading to the flash floods, many of these warnings weren’t taken seriously. What makes this disaster unusual is that it was so sudden, coming without warning.

The immediate priority should be to search for missing people and local communities can help do this. Nepal is a very collective society and locals will have a better idea of how to locate missing people than those without local knowledge.

Shelter and food will be essential to meet immediate needs. Local communities who can work with agencies to oversee the logistical hurdles to deliver essential goods and services. They will also be key to mapping the location of available shelters and storage facilities e.g. schools, gumbas (Buddhist monasteries) in the immediate aftermath of this disaster. These facilities will be important distribution centres for essential goods and services, and serve as community hubs.”

"I’m yet to fully appraise myself of the situation, but these floods are probably 'glacial lake outburst floods' (GLOFs); these are increasingly common in alpine regions globally as our climate changes.

As glaciers melt and recede, ice turns to water, the water is stored (temporarily) behind natural moraine dams, but when those dams breach, tremendous amounts of water can be released down a valley, taking out everything in its path.

I was meant to be in the Indian Himalaya now, studying GLOFs, with Indian glaciological colleagues."

"This is a terrible and overwhelming event, triggered by natural phenomena and worsened by the location of villages along the river edge.

Right now, the focus is on life-saving and getting aid to those affected, including food, water, shelter, warm clothes and blankets.

As with many Himalayan disasters, access can be a problem. The best thing aid agencies can do is to support the efforts of local organisations."

"Scientists from the International Centre for Integrated Mountain Development in Kathmandu and China's earth science agencies are suggesting that there was an outburst flood-landslide on the Nepal side of the border in the Everest region that travelled into the Tibetan Autonomous Region before charging down the Bhote Koshi River into Nepal.

It operated like an inland Tsunami, travelling nearly 170 kilometres down the Bhoti Koshi valley into Central Nepal. This is the main highway joining Kathmandu to Lhasa, and it is a popular route for international tourists travelling from Kathmandu to Lhasa.

I was going to take this route on Sunday."

"The flash flood disaster in Nepal is tragic. Though the exact cause of the event requires further investigation, the steep and narrow valleys in the region would contribute to its devastating nature of deep, fast flowing and debris laden water.

The Himalayan Region has had a history of deadly flash floods. The event appears to have occurred without warning, catching those downstream unaware. Research shows that early warning saves lives and there are efforts globally to improve early warning systems.

Attention of authorities will now shift to downstream search and rescue and relief for communities impacted."