Nepal: Heavy rainfall, consequent flooding and landslides leave at least 66 people dead across country as of Sept. 28

Monsoon-related heavy rainfall has affected much of Nepal since Sept. 27, causing flooding and landslides that had killed at least 66 people, injured some 60 others, and left at least another 69 missing across the country as of Sept. 28. Most of the reported deaths are from the Kathmandu Valley. The casualty count will likely rise over the coming days as rainfall is forecast to continue in parts of the country into at least Sept. 29.

The rainfall, flooding, and landslides have inundated thousands of homes, blocked roads and highways across the country, disrupted domestic flights, and caused electricity and internet disruptions in some areas, including Kathmandu. Governmental authorities have discouraged nonessential vehicular travel amid the flooding and banned buses from traveling on highways at night as well as nighttime road travel in the Kathmandu Valley. Officials have mobilized thousands of members of the country's security forces, including police officers and military personnel, to assist in search and rescue operations.

As of Sept. 28, Nepal's Department of Hydrology and Meteorology had issued red warnings (highest level on a four-tier scale) for heavy rainfall across much of the country. Officials also issued orange and yellow rainfall warnings for the rest of country, including some western, northern, and eastern regions. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Further sustained heavy rainfall could trigger additional flooding in low-lying communities near rivers, streams, and creeks. Further urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Additional landslides are possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Floodwaters and debris flows may render additional bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close additional routes that become inundated by floodwaters. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and track inundation. Severe weather will also probably trigger further flight delays and cancellations at airports in the region.

Significant business disruptions will likely occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Flooding could heighten the threat of disease outbreaks. Backflow from drains mixed with floodwaters can become trapped in open areas when inundations recede. These stagnant pools often become a breeding ground for mosquitoes and bacteria, increasing the incidence of insect- and waterborne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.