By Morshadur Rahman

DHAKA, April 26, 2024 (BSS) - Bangladesh today set all-time heatwave record as the Met Office recorded 24 days of heatwave during the current month of April breaching previous 23 days of heatwave in 2019.

"Twenty-three days of heatwaves were logged during two months of April and May in 2019, which were considered the prolonged heatwaves in the history of the country. But the April alone crossed the grim milestone setting new record of heatwave days," Dr Abul Kalam Mallik, meteorologist of Bangladesh Meteorological Department (BMD) told BSS today.

The ongoing heatwave will continue until the next month meaning the number of days of heatwave is expected to increase this year, he said, adding alongside alarmingly rise heatwave in a single year, Bangladesh has already set another record of severe and very severe heatwave days, indexes of measuring hot weather.

Explaining the three key indexes of hot weather  - - heatwave, severe heatwave and very severe heatwave, the BMD meteorologist said, "We considers temperatures above 36 degrees Celsius for at least two consecutive days as heatwaves while temperatures between 40 degrees and 42 degrees are severe heatwaves and temperature of above 42 degree Celsius are very severe heatwave."

Mallik said severe heatwaves are sweeping in the country since April 19 and severe and very severe heatwaves are continuing meaning the country already witnessed eight days of severe and very severe heatwaves.

According to the previous data of BMD, the numbers of days of severe and very severe heatwaves were between one and seven days in the country, he added. But this year, prolonging severe and very severe heatwave already have exceeded the previous record.      

The weather expert said earlier, the western and northern regions -- Khulna, Rajshahi, Rangpur of Bangladesh are considered heatwave-prone areas. Some south-western parts of Barishal division and Dhaka division experienced heatwave, he continued.

"Since the 90s, days of heatwave have been increasing alarmingly in Bangladesh giving a clear signal that the country may face prolonged heatwaves . . . Simultaneously heatwaves are spreading across the country," Mallik added.

"Once, heatwaves were confined in the western, northern and central parts of Bangladesh. But this year the entire country witnessing heatwaves. It means weather pattern in Bangladesh has changed drastically extending heatwave coverage areas with its intensity," he added,    

According to the BMD collected data, 18 days of heatwave were recorded between April 13 and 14 in Dhaka in 1999, 13 days of heatwave were posted in Dhaka in May in 2004 and 18 days, 19 days, 20 days of heatwave in Jashore in 2014, 2016 and 2017 respectively.

The BMD also added that 13, 10, 17 days and 13 days of heatwave were reported in 2014, 2016, 2019 and 2022 in Rajshahi respectively while 19 and 23 days of heatwave in 2014 and 2019 respectively in Chudanga.

Mallik blamed reduction of thunderstorm for increasing of heatwaves in the country as only one thunderstorm occurred in April this year while the Met Office recorded four thunderstorms in 2021, 9 thunderstorms in 2022 and seven in 2023. Frequency of thunderstorm was much higher than recent years, he said adding thunderstorm has made contribution to reduce hot weather.        

The entire country is reeling under first spell of severe heatwave since first week of the current month and the ongoing heatwave will persist throughout the next month.

"The Met Office issued heat alert on April 3 and it has extended the heat alert as Bangladesh is likely to experience prolonged heatwave compared to the past of couple of years," Shahnaz Sultana, a meteorologist of Bangladesh Meteorologist Department (BMD), told BSS recently.

Very Severe heat wave is sweeping over the districts of Chuadanga & Jashore and severe heat wave is sweeping over rest part of the Khulna division & the districts of Tangail, Faridpur, Gopalgonj, Manikgonj, Rajshahi, Pabna, Dinajpur & Nilphamari. Mild to moderate heat wave is sweeping over Barishal division and the districts of Dhaka, Madaripur, Kishoregonj, Narsingdi, Bagura, Naogaon, Sirajgonj, Rangpur, Kurigram, Panchagarh, Mymensingh, Maulovibazar, Rangamati, Chandpur, Feni & Bandarban and it may continue, a weather bulletin of BMD said today

The Met office today recorded maximum temperature 42.4 degrees Celsius at Jashore while 20.6 degree Celsius at Tetulia in Rangpur.  

 Climatologist and Senior Scientific Officer of Bangladesh Rice Research Institute Dr Md Kamruzumman Milon attributed the extreme heatwave to human-induced climate change.

Adverse impact of climate change causes extreme heatwave for longer period of time and unusual other disaster events including flooding, excessive rainfall and extreme cold weather.

Heatwave and intolerable hot weather have increased three times in Bangladesh during six decades, Kamruzzaman said, "In 1961, the duration of heatwave was seven days while comfortable days were 80 while in 2020, the duration of heatwave was 21 days while comfortable days were 66 days."

He forecasted duration of heatwave will linger in the coming days, "If we fail to take proper adaptive measures to reduce carbon emission."