In the past four and a half decades, Bangladesh never saw monsoon, the rainy season officially comprising the four months from June to September, arrive as early as it did this year.
The Bangladesh Meteorological Department on May 24 recorded the arrival of monsoon up to Cox鈥檚 Bazar. On Monday, the BMD said, monsoon advanced up to the eastern part of Dhaka with environmental conditions favouring its progress further inland on the day.
Wide columns of cloud invaded Dhaka鈥檚 skies on Monday, bringing more than a half hour of rain in the afternoon. Sylhet recorded 131 mm of rainfall in the 24 hours until 6:00pm on Monday.
The BMD on Monday also issued a heavy rainfall and landslide warning with a forecast of light to moderate rainfall in most places of聽 Bangladesh until next Friday.
Monsoon refers to a shift in the flow of wind. The season, vital for the agriculture and economy for one of聽 the world鈥檚 most populous, poverty-ridden and disaster-prone countries, brings moisture-rich air from oceans in the southwest over to the vast land masses in South Asian and Southeast Asian regions.
鈥楩requent spells of rain during the early monsoon arrival could be a hint of a wetter rainy season this year,鈥� meteorologist Hafizur Rahman told 抖阴精品.
A low pressure area is likely to form over the north Bay of Bengal today, potentially causing widespread precipitation in Bangladesh and its upstream areas in India and Nepal over the subsequent seven days. There is also a chance 鈥� though slight 鈥� of the low pressure turning into a cyclonic storm.
Heavy rains across the upstream hilly regions of the mighty Himalayan range could unleash flash flooding and trigger deadly landslides.
Broadly, the arrival of monsoon is considered a relief for the densely populated Asian regions where the temperature often exceeds 40C for days in a row during the pre-monsoon months from March to May.
Monsoon follows the hot months that pave the way for the season to arrive by heating vast land masses, causing the air from high pressure ocean areas to flow toward the low-pressure land areas.
The moist air cools as it travels through higher land over the great Himalayan landscape, losing its capacity to hold moisture, and causing rains.
The pre-monsoon months this year were rather less warm as the day temperature rarely touched the 40C threshold because of frequent spells of thunderstorms.
Last year, Bangladesh recorded the third earliest arrival of monsoon, which was rather dry with large rain deficits recorded in the months.
In the 44 years since 1981, according to the Changing Climate of Bangladesh report released by the BMD in 2024, the monsoon arrived at Bangladesh鈥檚 southeastern coast or northeast Bay of Bengal in late May 11 times, eight of them occurring since 2000.
In 2009, monsoon arrived on May 26, the previous earliest onset of monsoon. Monsoon arrived in Chattogram on May 27 in 1999, the previous second-earliest date of its arrival. Weather data prior to 1981 are not reliable.
The monsoon in 2009 was spurred by the cyclonic storm Aila, which caused nearly $2 billion damage in India and Bangladesh, besides killing 340 people. The Flood Forecasting and Warning Center record shows that the flooding affected a fifth of Bangladesh in 2009.
In 1999, a severe flooding engulfed 32,000 square kilometres of area, accounting for 22 per cent of the overall land surface of Bangladesh.
Last year, the early onset of monsoon was facilitated by the cyclonic storm Remal that impacted the coastline badly, causing up to 300mm of rainfall in 24 hours after it hit on May 24.
Monsoon is the most important time of year in Bangladesh in terms of rainfall, accounting for 80 per cent of all rain in the country and India.
While replenishing groundwater reserves, the rain is the source of irrigation for tens of lakhs of impoverished farmers who also have few drinking water alternatives to natural water supply.
Besides, less warm and wet months mean less electricity consumption for both cooling and irrigation purposes. Less power consumption is one of the best things that could happen to Bangladesh, which is heavily depended on energy import now. Wetter monsoon could thus boost Bangladesh鈥檚 economy and reduce the country鈥檚 staggering inflation.
Monsoon can, however, bring more insects, diseases, and water stagnation to cities.
Monsoon has always been seen as a blessing for agriculture-based Asian economies, finding a core place in life. The importance of monsoon in Asian people鈥檚 lives is well reflected in its presence in spiritual and psychological realms. The Indian classical music raga Malhar is dedicated to monsoon.
Excessive rain can also be dreadful for Bangladesh, particularly because of its deplorable water management capacity worsened by India鈥檚 arbitrary release of water from the upstream. Numerous barrages were built on the vast catchment of the Ganges, the Brahmaputra, and the Meghna basins in the upstream in India and Nepal.
These three river systems in Bangladesh drain massive runoff from 16 lakh sq km of areas. Bangladesh constitutes less than 8 per cent of the catchment areas of these river systems.
A mixed monsoon with an average rainfall can trigger dengue outbreaks as dengue vectors can thrive in certain conditions highly depending on rainfall and temperature.
Some of the last monsoons, including the one in 2023, were rain-deficient. Bangladesh recorded its worst inflation in decades over the past three years.
The past two years saw prolonged droughts during monsoon, leaving farmers in rural areas on their knees to pray for rain. In cities, severe power outages made life miserable, causing severe water crises and many heat-related diseases.聽聽
A study released by the BMD in the past year revealed that heatwaves became more frequent during monsoons, particularly after 2010, extending through September.
More heatwaves during monsoon imply the presence of more dry days and fewer wet days. The number of heatwaves, on the other hand, in the pre-monsoon month of March substantially declined, revealed the study covering the timeline between 1981 and 2023.
