Cyclone
Evidence of climate change and sea-level rise suggest that coastal communities of Bangladesh are likely to face more frequent cyclones and storm surge events in the future. A long-term trend of disasters in Bangladesh based on 120 years (1900- 2020) data from EM-DAT data (http://www.emdat.be/) suggests that cyclone is one of the most recurrent disasters, they cause huge economic loss and can be associated with some of the significant catastrophic events in the history of Bangladesh, such as 1970 Bhola Cyclone where roughly 500,000 lives were lost.
The FOREWARN cyclone expert group has been a strong advocate for the adoption of a locally-developed cyclone impact model, which has played a pivotal role in the utilization of the Cyclone Disaster Risk Financing (DRF) system. This model incorporates the Cyclone Classifier Model (CCM), a product of the Institute of Water and Flood Management at BUET.
Presently, FOREWARN is actively engaged in enhancing the precision of this model to capture cyclone impacts at even more granular levels, including at the union level, within the four coastal districts of Bangladesh: Satkhira, Khulna, Barguna, and Patuakhali. Our team of Youth Experts is exploring ways to leverage artificial intelligence (AI) and machine learning (ML) to elevate the model's operational capabilities to the next level.
Forecast
The Bay of Bengal experiences two peaks of cyclone activity: one in April-May (pre-monsoon) and another in October-November (post-monsoon). Cyclones cause most damage near their center, where strong winds, heavy rains, and storm surge concentrate. Bangladesh Meteorological Department (BMD) monitors cyclones through a comprehensive network and issues warnings. The Global Disaster Alert and Coordination System (GDACS) collaborates with the UN and the European Commission to provide early alerts and risk analysis for cyclones globally. GDACS considers wind strength, rainfall, and storm surge for risk assessments. Alerts are issued based on factors like wind speeds affecting a significant population or heavy rainfall accumulation. Storm surge alerts are triggered by predicted water heights above certain thresholds in coastal areas. GDACS updates forecasts every six hours, and alerts serve as early warnings before the cyclone affects the population.
Impact
Bangladesh, located in the Bay of Bengal, faces frequent cyclonic hazards due to its geographical position and low-lying topography. Storm surges during pre-monsoon and post-monsoon seasons can reach up to nine metres, causing significant loss and damage. The country's coastal line, over 700 kilometres, lies within the tropical cyclone-prone zone. The high population density and shallow coastal front exacerbate the exposure to cyclones. Since 1970, cyclones and storm surges in Bangladesh have resulted in 363,378 lives lost. Although advancements in early warning systems and evacuation have reduced deaths, economic damages are increasing. Cyclone impacts include deaths, economic losses, affected population, displacement, and property damage. Cyclone Amphan in the previous year caused the highest economic loss of $1.5 billion, along with significant death and displacement. Cyclone Komen affected 2.6 million people, the highest number recorded. In 2019, cyclones Fani and Bulbul resulted in 52 deaths and displaced 3.68 million people. Cyclones and storm surges are the most frequent climate-related disasters in Bangladesh, with a calculated risk index indicating varying impacts across districts: very high in 2 (11.74%), high in 2 (11.76%), medium in 6 (35.29%), low in 6 (35.29%), and very low in 1 (5.80%) district.