Bay of Bengal: Cyclonic Storm Mandous tracking west-northwestward in the southwest Bay of Bengal as of early Dec. 9 /update 1

Event

Cyclonic Storm Mandous is tracking west-northwestward in the southwest Bay of Bengal as of early Dec. 9. As of 05:30 IST, the storm's center of circulation was approximately 269 km (167 miles) south-southeast of Chennai, India.

Forecast models indicate that the storm will weaken as it tracks west-northwestward towards northeastern Tamil Nadu State, India, before making landfall as a cyclonic storm near Puducherry late Dec. 9. After landfall, Mandous is forecast to weaken rapidly as it tracks west-northwestward across northern Tamil Nadu State before dissipating over the far northwestern part of the state late Dec. 10. The storm's track and intensity forecast remain somewhat uncertain, and changes may occur over the coming days.

As of early Dec. 9, the India Meteorological Department has issued the following warnings:

• Red (highest level on a three-tier scale) heavy rainfall and strong wind warnings: Tamil Nadu State Dec. 9

• Orange heavy rainfall and strong wind warnings: Andhra Pradesh State Dec. 9; Tamil Nadu and western Andhra Pradesh states Dec. 10

• Yellow heavy rainfall and strong wind warnings: the rest of the affected area through Dec. 12

The Sir Lanka Department of Meteorology has also issued an amber cyclone advisory (the middle level on a three-tier scale) for coastal areas and an amber heavy rainfall and strong wind advisory for Northern, North-Central, Eastern, Uva, and Central provinces due to the passing of the storm. Officials will likely issue new alerts or update/rescind existing advisories as the storm progresses.

As of early Dec. 9, authorities in Tamil Nadu State have established around 5,000 relief camps across the state to relocate people in low-lying areas. A further 238 relief camps have been established in Puducherry Union Territory. Schools have been closed in several parts of the affected area from Dec. 9, including Chennai.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible if weather conditions prove hazardous.

The inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary closures of ports are also possible. Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Raw sewage and other hazardous materials mixed with floodwaters pose a serious health threat.

Advice

Activate contingency plans in areas where officials forecast adverse weather conditions. Heed any evacuation orders that may be issued. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the potential for severe flooding and storm surge. Stockpile water, batteries, and other essentials in advance. Charge battery-powered devices when electricity is available; restrict the use of cellular phones to emergencies only. Power down mobile devices when not in use. Keep important documents and necessary medications in waterproof containers. Take precautions against insect- and waterborne diseases in the coming weeks.

Plan accordingly for protracted commercial, transport, and logistics disruptions in areas in the path of the storm, especially if vital infrastructure is damaged. Seek updated information on road conditions before driving or routing shipments through areas where flooding has occurred. Confirm flights before checking out of hotels or driving to the airport; clearing passenger backlogs may take several days in some locations.

Resources

Joint Typhoon Warning Center
India Meteorological Department