Two powerful landslides (energy equivalent to a 5.2 Richter scale ) happened within a 3-hour gap. When massive rocks roll down the mountain, they generate plenty of heat, melting the glaciers and causing massive floods. The floodwater was 130-160 ft high and flowed at 44 miles per hour.
The mean temperature has increased by 1.71C in Nepal recently, causing shorter monsoon seasons, more intense rainfall and shifting precipitation patterns, higher temperatures, and droughts. 80% of Nepal’s rainfall occurs between June and September. In parallel, loads of construction happens without proper infrastructure planning. Roadside landslides are increasing; dykes are built along river segments, attracting more people to settle in dangerous places along roads in floodplains, not because they are unaware of the physical danger but because of the economic opportunities such places bring
There are 3 major challenges in predicting these landslides and floods to avoid disaster.
- The lack of continuous and reliable local precipitation data
- The topography of the Himalayan range is extreme and complex to study.
- The pattern between the monsoon rainfall and ENSO (El Nin˜o Southern Oscillation) is changing.
Dharan is one of the major trading cities in Nepal,, located below the Siwalik foothills at 400–500 m above sea level. This is where the British created the “ Gurkha Center”. This city is flanked by two larger rivers – the Sardu Khola to the west and Seuti Khola to the east – and is bisected by several smaller rivers crossing the city – the Khahare Khola and Turke Khola. All of the streams are subject to flash flooding. Urban runoff, encroachment of settlements on riverbanks and in river channels themselves, poorly maintained canalizations, upstream deforestation, and increasingly intense monsoon rains have together led to severe flash floods and landslides here, killing many residents instantly.
People living here rebuild their houses almost once a year because of flooding. So the people who live here are well aware of floods and landslides, but they can’t move out as the cost of living in “safe areas” is higher, which is not affordable for the marginalized community.
The priority of the local municipality is providing clean drinking water, education, and garbage disposal. Flood-related risk is the last priority. The local govt doesn’t have high-end technologies; they depend on basic tools like GIS, but old versions of the software, low-performing computers, and virtually no data useful for a GIS database. They also lack data on local rainfall and topography.
Nepal’s current development model is based on infrastructure development, not capacity building. Without capacity building, climate change models will remain inaccessible. The answer lies not in the tool (i.e., climate change scenarios and impact models) but in how the tool is used.
This requires good governance, resources, political willingness, and community participation, not just better data.