India: Adverse weather forecast to continue across northeastern regions through at least May 7 /update 1

Severe weather is forecast to continue across northeastern India through at least May 7. Heavy rainfall and thunderstorms have been ongoing in recent days and the Indian Meteorological Department (IMD) has issued a press release May 3 warning another spell of severe weather is expected May 5-6. Widespread light-to-moderate rainfall with thunderstorms and strong winds is likely across the region May 3-7, with isolated heavy-to-very heavy rainfall expected May 5-6.

The IMD has issued the following severe weather warnings across the affected area May 3-7:

• Orange heavy rainfall, thunderstorm, and lightning warnings (the middle level on a three-tier scale): Assam, Manipur, Meghalaya, Mirozam, Nagaland, and Tripura May 5-6 and Arunachal Pradesh May 5.

• Yellow heavy rainfall warnings: Sikkim and Sub-Himalayan West Bengal May 5 and Arunachal Pradesh May 6.

• Yellow thunderstorm and lightning warnings: Assam, Manipur, Meghalaya, Mirozam, Nagaland, and Tripura May 3-4 and May 7, Arunachal Pradesh May 3-4 and May 6-7, and Sikkim and Sub-Himalayan West Bengal May 4-7.

Officials could update and extend the coverage of weather alerts over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. 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. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil.

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 some 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 some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at regional airports.

Localized business disruptions may 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 water-borne diseases. Exposure to contaminated water from inundated industrial sites, sewer systems, and septic tanks also poses a significant health threat.