Environment: Cyclone Amphan tracking northeastward in Bay of Bengal as of May 20. Landfall is likely in eastern West Bengal State, India, late May 20.

Severity: Critical Alert

The locations affected by this alert are:

  • Bangladesh
  • Bhutan
  • Kolkata, West Bengal State
  • Guwahati, Assam State
  • Bhubaneshwar-Cuttack, Odisha State
  • Haldia, West Bengal State
  • Biratnagar
  • Paradip, Odisha State
  • Darjeeling, West Bengal State
  • Jamshedpur (Tatanagar), Jharkhand State
  • Shillong, Meghalaya State
  • Agartala

This alert began 20 May 2020 12:26 GMT and is scheduled to expire 22 May 2020 23:59 GMT.

  • Incident: Very Severe Cyclonic Storm Amphan
  • Affected Area(s): Bangladesh; Bhutan; eastern India; western Myanmar (map)
  • Projected Landfall (Date): Eastern West Bengal State, India (late May 20)
  • Center of Circulation: 239 km (148 miles) south-southwest of Kolkata, India
  • Maximum Sustained Winds: 85 knots (160 kph, 95 mph)

Summary
As of May 20, Very Severe Cyclonic Storm Amphan - a Category-2 hurricane equivalent - is weakening as it continues to track north-northeastward toward eastern India and Bangladesh in the Bay of Bengal. As of 1200 BST May 20, the system's center of circulation was approximately 239 km (148 miles) south-southwest of Kolkata, India. The system is forecast to weaken before its projected landfall over eastern West Bengal State, India, late May 20. The storm will then continue to weaken into a cyclonic storm and then a depression as it traverses Bangladesh, May 21. Amphan is expected to dissipate over Bhutan, May 22. There remains some uncertainty in the track and intensity forecast, and significant changes could occur in the coming days.

Government Advisories
The India Meteorological Department has issued heavy rainfall, thunderstorm, and strong wind warnings for eastern India, including portions of West Bengal, Bihar, Sikkim, Assam, Meghalaya, Arunachal Pradesh states. Officials also warn of potential storm surges over low-lying areas in the East Medinipur district of West Bengal close to landfall May 20.

Bangladesh Meteorological Department has raised the maritime ports of Mongla and Payra, as well as Satkhira, Khulna, Bagherhat, Jhalokathi, Pirozpur, Borguna, Patuakhail, Bhola, Barishal, Laxmipur, and Chandpur to Great Danger Signal Number 10. Additionally, Chattogram, Cox's Bazar, Noakhali, and Feni have been placed under a Great Danger Signal Number 9. The agency also warns of strong winds and adverse sea conditions and is advising fishers to remain close to coastal areas.

Bhutan's National Center for Hydrology and Meteorology has issued a storm advisory for heavy rainfall and flooding for the southern and eastern parts of the country as of May 20.

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. The possibility of localized evacuations cannot be discounted if weather conditions prove particularly hazardous. Millions of people across India and Bangladesh have been evacuated, as of May 21, ahead of the storm's arrival. Additional evacuation orders are possible over the coming days as Amphan nears landfall.

Hazardous Conditions
The storm will continue to bring heavy rainfall, strong winds, and rough seas to coastal areas along the Bay of Bengal through at least May 21. Forecast models indicate widespread rainfall totals of 10-25 cm (4-10 inches) are likely across Odisha and West Bengal, India, as well as much of Bangladesh. Locally higher totals are possible in areas that experience persistent heavy rain bands. Sustained heavy rainfall could trigger flooding in low-lying communities near streams, creeks, and rivers, as well as in urban areas with easily overwhelmed or a lack of stormwater drainage systems. 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. Coastal flooding may also occur during moderate storm surges. Persistent onshore flow could make it difficult for a surge to recede and for water levels to decrease in coastal river catchments. Given its low-lying, riverine geography, Bangladesh is especially at risk of flooding.

In addition to the heavy rain, flooding, and storm surge, the system will produce damaging wind gusts up to 195 kph (120 mph), especially in areas close to the center of circulation. Widespread and prolonged power outages due to uprooted trees and toppled utility lines are likely.

Transport
Inclement weather associated with the storm could trigger localized business, transport, and utility disruptions through at least May 22. Impacts from the storm will further exacerbate transportation disruptions already occurring in areas under restrictions due to coronavirus disease (COVID-19) activity. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Areal flooding in urban locations could also result in severe traffic congestion, while strong winds will pose a hazard to high-profile vehicles. Heavy rain and low visibility may trigger flight disruptions at regional airports. Hazardous sea conditions could prompt the temporary suspension of ferry services, maritime shipping, and port operations in areas near the storm's path.

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.

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): www.metoc.navy.mil
Bangladesh Meteorological Department: live3.bmd.gov.bd
National Center for Hydrology and Meteorology (Bhutan): www.nchm.gov.bt
Indian Meteorological Department: https://mausam.imd.gov.in