Bay of Bengal: Very Severe Cyclonic Storm Hamoon tracking east-northeastward towards southeastern Bangladesh Oct. 24 /update 1

Event

Very Severe Cyclonic Storm Hamoon is tracking east-northeastward in the Bay of Bengal Oct. 24. As of 18:00 BST, the storm's center of circulation was approximately 256 km (159 miles) southwest of Chattogram, Bangladesh.

Forecast models indicate that the system will weaken slightly into a severe cyclonic storm as it tracks northeastward towards southeastern Bangladesh Oct. 24, before making landfall to the north of Cox's Bazar in Chattogram Division in the early hours of Oct. 25. After landfall, Hamoon is expected to weaken further into a cyclonic storm and then a depression as it tracks northeastward across Chattogram Division and Mizroam State in India through Oct. 25, before dissipating over Manipur State Oct. 26. The storm's track and intensity forecast remains somewhat uncertain, and changes may occur over the coming hours and days.

As of Oct. 24, the Bangladesh Meteorological Department has advised the maritime ports of Chattogram and Payra to hoist Danger Signal No. 7 (level 7 on a ten-tier scale), Cox's Bazar Danger Signal No. 6, and Mongla Danger Signal No. 5 due to the system's approach. Coastal districts of Barisal, Patuakhall, Bhola, Borguna, Pirozpur, Jhalokathi, Chattogram, Feni, Noakhali, and Laxmipur and their offshore islands and chars are under Danger Signal No. 7; storm surge of 0.9-1.5 meters (3-5 feet) above the normal tide is possible in areas of onshore winds. Authorities have advised people in at-risk areas of coastal Bangladesh to evacuate to shelters by 20:00 Oct. 24. Coastal districts of Khulna, Bagherhat, and Satkhira and their offshore islands and chars are under Danger Signal No. 5. Rainfall totals of 4.4-8.8 cm (1.7-3.5 inches) are forecast across parts of Barisal, Chattogram, Dhaka, Khulna, and Sylhet divisions, with localized heavier downpours possible. Heavy rainfall may trigger landslides in elevated areas. Authorities have advised all vessels in the North Bay to remain in shelter until further notice.

The India Meteorological Division has warned of light-to-moderate rainfall with isolated heavy downpours over parts of northeastern India Oct. 24-26. Yellow heavy rainfall warnings (the lowest level on a three-tier scale) have been issued for Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura states Oct. 24-25. Myanmar's Department of Meteorology and Hydrology has forecast widespread rainfall and thunderstorms across western, northern, and north-central regions, with isolated heavy downpours.

Officials will likely issue new alerts or update/rescind existing advisories as the storm progresses.

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
Bangladesh Meteorological Department
India Meteorological Department
Myanmar Department of Meteorology and Hydrology