Gulf of Mannar: Deep Depression Burevi tracks toward southern India Dec. 3; landfall forecast in southern Tamil Nadu State early Dec. 4. /update 3

Event

Deep Depression Burevi is tracking westward in the Gulf of Mannar, Dec. 3. As of 1730 IST, the storm was located approximately 125 km (76 miles) southeast of Madurai, India. Forecast models indicate the system will weaken following a second landfall forecast in southern Tamil Nadu State early Dec. 4. The Burevi is projected to enter the Bay of Bengal on Dec. 5, where it will likely restrengthen to a cyclonic storm. Some uncertainty remains, and the track and intensity forecast is subject to change over the coming days.

Government Advisories
As of Dec. 3, the Indian Meteorological Department issued red- and orange-level warnings for heavy rain, thunderstorms, and strong winds in Tamil Nadu, Puducherry, and Kerala. Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days. Weather warnings could remain active even after the system's immediate threat has diminished, as some areas may still be highly susceptible to rain-induced hazards.

In advance of the storm, residents in low-lying areas of Kerala State have been ordered to evacuate; further, localized evacuation orders may be issued as Burevi approaches the region.

Hazardous Conditions
The system will continue to bring heavy rainfall, strong winds, and rough seas to much of southern India and Sri Lanka through at least Dec. 5. Forecast models indicate widespread rainfall totals of 25-50 cm (10-20 inches) are likely across the hardest-hit areas near the center of circulation, including northern and central Sri Lanka, and southeastern Tamil Nadu. Lower amounts of 10-25 cm (4-10 inches) are forecast in interior Tamil Nadu, while 5-10 cm (2-4 inches) are expected in southern Sri Lanka and Kerala State, India. Locally higher totals are possible in areas that experience persistent bands of thunderstorms. Flooding is especially possible in low-lying communities near streams, creeks, and rivers, as well as in urban areas with easily overwhelmed stormwater drainage systems and in locations that were previously impacted by Cyclonic Storm Nivar. Sites located downstream of large reservoirs could experience flash flooding after relatively short periods of intense rainfall. Rain-induced landslides are possible in steeply sloped terrains. Flooding could isolate some communities for several days. Prolonged swells and storm surge generated by the system will likely result in coastal flooding. Persistent onshore flow could make it difficult for a surge to recede and for water levels to decrease in coastal river catchments.

In addition to the heavy rain, flooding, and storm surge, the system will likely produce damaging wind gusts up to 40 knots (74 kph, 46 mph), especially in areas near and to the north of the center of circulation. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are possible.

Transport
In addition to the immediate threat to personal safety, inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least Dec. 3 in Sri Lanka and Dec. 5 in southern India. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Disruptions triggered by inclement weather and resultant hazards, such as flooding, could persist well after conditions have improved. If there is severe damage to infrastructure, repair or reconstruction efforts may exacerbate residual disruptions. Heavy rain and low visibility may trigger flight disruptions at regional airports.

Health
Stagnant pools of water during and after flooding increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. The threat of these disease outbreaks is usually elevated in the low-income or underdeveloped areas of major urban centers due to the presence of incomplete or open sewer lines. The latent threat of waterborne contaminants from inundated industrial sites cannot be discounted; exposure to raw sewerage and other hazardous materials mixed with floodwaters poses a serious health threat.

Advice

Activate contingency plans in areas where officials forecast tropical storm conditions. Heed all evacuation orders. Use extreme caution in low-lying coastal areas and near streams, creeks, and other waterways due to the high 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 in waterproof containers. Observe strict food and water precautions, as municipalities could issue boil-water advisories following flooding events. Take precautions against insect- and waterborne diseases in the coming weeks. Keep any necessary medications in a waterproof container.

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 (JTWC)
Sri Lanka Department of Meteorology
India Meteorological Department