According to weather alerts issued by the Met Office on Sunday, Bangladeshis have been experiencing mild to moderate heatwave at present, and the condition would likely to continue for the next five to six days
Published : 04 Jun 2023, 09:07 PM
Jasmine Nahar, a 50-year-old resident in Dhaka, has been contemplating whether to run some outdoor errands for the last few days.
Those errands are related to her business and must be completed as soon as possible. However, she is terrified of the sweltering weather that has no indication to ease up any time soon.
“I need to get out to run some errand, but the heat outside was enough to put me off. Severe headache caused by heat from the sun has been a lifelong issue for me, so I chose to wait until the temperature drops a little bit. However, the discomfort inside my place due to the heatwave is becoming unbearable,” Jesmine said.
Bangladeshis, according to weather alerts issued by the Met Office on Sunday, have been experiencing mild to moderate heatwave, and the condition will likely continue for the next five to six days.
WHAT IS A HEATWAVE?
- According to the World Health Organisation, a heatwave is generally defined as a period of at least five days where temperatures in an area are five degrees Celsius above the daily average. However, the specific parameters can vary according to country and region.
- The Bangladesh Meteorological Department defines temperatures of 36 to 38 degrees Celsius as a mild heatwave, 38 to 40 as a moderate heatwave and temperatures above 40 degrees Celsius as an intense heatwave.
The government has already ordered shutdown of the state-run primary schools from Jun 8, considering the impact of the heatwave on children.
Meteorologist Dr Muhammad Abul Kalam Mallik said the chances of the temperature easing up before Jun 13 are slim.
“Heavy clouds will start to form from Jun 12, and the chances of rain across the country are high from Jun 13, which I believe will bring the mercury down to some degrees,” he said.
On Sunday, people in Dinjapur experienced a 41.1 degree Celsius temperature, the highest temperature in the country. Dhaka’s temperature was 37.6 degrees Celsius.
The people in Rajshahi felt the highest temperature the day before, at 41 degrees Celsius. Dhaka’s temperature was 37.1 degrees Celsius.
The Met Office has predicted a severe heatwave over Rajshahi, Naogaon, Nilphamari and Dinajpur districts in the next 24 hours.
According to an alert, a mild to moderate heat wave is prevailing over Dhaka, Mymensingh, Khulna, and Barisal divisions along with remnants of Rangpur and Rajshahi divisions and Moulvibazar, Chandpur and Noakhali districts and may persist.
This year, as soon as the summer kicked in, the mercury rose to an exceptional level, especially in April.
By mid-April this year, Khulna, Rajshahi and Dhaka divisions and their surrounding areas were experiencing mild to moderate heatwaves. Rain and storms relieved some afterwards, but a moderate to intense heatwave returned at the end of the month.
On Apr 16, Dhaka saw the temperature reach 40.6 degrees Celsius, the highest in the city in 58 years.
Rajshahi has twice recorded temperatures of 41.2 degrees Celsius – the highest in the country so far this year. Eleven locations across the country recorded temperatures between 36 to 40 degrees Celsius in the 30 days of April.
The situation became so dire that the steel-made rail lines outside Brahmanbaria town started to bend due to the heat. Thanks to quick actions taken by the railways at the time, any major raid accident was averted.
The heatwave eased up a bit due to the influence left by Cyclone Mocha, a category four tropical cyclone, which made landfall mainly in Myanmar and part of Bangladesh's coast on May 14.
However, as soon as the influence of the cyclone dissipated, the temperature started to rise again.
Projections made before the beginning of the summer, however, indicated that the temperature in Bangladesh would gradually rise during summer periods.
A World Bank report in 2021 cautioned that average temperature rises in Bangladesh are broadly in line with the global average.
“Bangladesh will experience emerging hot and humid seasons, in which the Heat Index surpasses 35 degrees Celsius,” reads the report.
HISTORICAL DATA ON HEATWAVES IN BANGLADESH
- A 2019 Study on Heatwaves and Associated Large-Scale Circulation in Bangladesh gives a general idea of where the highest temperatures in the country were recorded between 1981 and 2016.
- According to co-author Mohan Kumar Das, one of the most prolonged heatwaves in the country was recorded in Chuadanga and Ishwardi in 1995, with 62 days of temperatures above 36 degrees Celsius. Another heatwave lasted 60 days in Jashore in 2010, while a third in Rajshahi in 1994 dragged on for 55 days. In 2014, a heatwave lasted 79 days in Rajshahi, 51 in Mongla and 50 in Khulna.
WHAT OTHER FACTORS CONTRIBUTED TO THE HEATWAVE
Dr Mallick pointed out that the ongoing heatwave is so unbearable because of the high humidity level in the air.
“Global warming has affected Bangladesh. Moreover, the sky here is almost cloudless as El Niño is set to be active, causing the wind speed to go lower, and the water vapour in the air is high; hence people’s discomfort is more. The temperature in all the countries surrounding Bangladesh is high now.” he said.
WHAT IS EL NIÑO AND HOW IT AFFECTS SOUTH AND SOUTHEAST ASIA?
- El Niño is a unique state of the global climate, which warms the surface waters of the equatorial Pacific Ocean, affecting the ionosphere and surrounding climate.
- Dr Mallik said as El Niño is active, Haryana, Rajasthan, Uttar Pradesh, Madhya Pradesh, Delhi, Bihar, West Bengal, Meghalaya, Tripura, Nagaland, Arunachal, Myanmar, Vietnam, Cambodia, Thailand, Pakistan, Afghanistan, along with Bangladesh; This entire region is now acting as a ‘heat engine'.
MONSOON IS SET TO ARRIVE. BUT THERE’S HARDLY ANY RAIN. WHY?
In the cycle of seasons, the middle of June is called the Monsoon season in Bangladesh. During this time, the southwest monsoon from the Indian Ocean makes landfall, resulting in heavy rain and officially ending the Summer season in Bangladesh.
Usually, the southwest monsoon arrives in early June with rainfall, but according to Dr Mallik, there are indications that the Monsoon will be delayed this year.
"A low pressure is likely to form in the Bay of Bengal off the coast of Myanmar on Jun 7, and a different low pressure is still present in the Arabian Sea. The onset of monsoon over Bangladesh and India may be slightly delayed because of these two depressions,” he said, adding that the temperature in the northwestern and southwestern parts of the country has been behaving abnormally in the first week of June for the last few years.
“Monsoon usually starts in the first week of June in the Chittagong Division and takes until June 14 to spread across the country. But in recent years, especially since 2015, monsoons are late to start and spread over Bangladesh."
“This year, we may have to wait until the third week of June for Monsoon to kick in,” says Dr Mallik.
[Writing in English by Adil Mahmood; editing by Biswadip Das]