Patna: Although the southwest monsoon reached Bihar four days ahead of schedule this year, its progress has stalled for the past 10 days, leaving large parts of the state grappling with intense heat and dry conditions.
The monsoon arrived in Bihar on June 11, earlier than its usual onset date of June 15. However, it has yet to advance into several districts, including Kaimur, Rohtas, Aurangabad, Gaya, Arwal, Bhojpur, Buxar, Saran, Siwan, Gopalganj, Patna, Nalanda, Jehanabad, Nawada and Jamui.
With temperatures crossing 42 degrees Celsius in many areas, residents are facing severe discomfort while concerns are mounting over the impact on public health and agriculture.
According to Dr. Anand Shankar, Senior Scientist at the Meteorological Centre in Patna, widespread rainfall is expected to begin across Bihar from June 25.
“Satellite imagery indicates that cloud formation is increasing. Conditions are becoming favourable for the monsoon to advance further into Bihar around June 23,” he said.
Why Has the Monsoon Stalled?
Dr. Shankar explained that while the monsoon arrived on time, it has not been able to cover the entire state due to multiple atmospheric factors.
“The monsoon does not advance uniformly in all directions. Its movement depends on several interconnected weather systems,” he said.
He identified a high-pressure system near Madagascar, the position of the Tibetan anticyclone, the tropical easterly jet stream and heat conditions over the Thar Desert as key factors influencing the monsoon’s progress.
“These conditions are currently not favourable for the monsoon to intensify over Bihar as expected,” he added.
Key Weather Systems Influencing the Monsoon
The Madagascar high-pressure system, located over the southern Indian Ocean near the island nation of Madagascar, plays a crucial role in generating winds that cross the equator and strengthen the southwest monsoon over India.
The Tibetan anticyclone, a high-pressure system that forms over the Tibetan Plateau during summer, helps generate the tropical easterly jet stream. This jet stream supports the movement and strengthening of monsoon winds across the Indian subcontinent.
Meanwhile, intense heating over the Thar Desert creates a low-pressure trough that draws moisture-laden monsoon winds inland. Weakening of this system can slow monsoon advancement.
Rainfall Outlook for Bihar
While districts in north and east Bihar have continued to receive intermittent rainfall, precipitation has largely stopped across southern parts of the state.
“Heatwave conditions are more pronounced in districts such as Kaimur, Rohtas and Buxar due to the stalled monsoon,” Dr. Shankar said.
He forecast widespread rainfall accompanied by thunderstorms in south Bihar between June 25 and 27.
“People are likely to experience some relief from the heat within the next two to three days, while temperatures across the state could decline significantly over the next five to six days,” he said.
At present, the monsoon trough is passing through areas near Madhubani and Munger, covering parts of eastern Bihar.
Monsoon Conditions Improving Across India
The India Meteorological Department (IMD) has indicated that conditions are becoming favourable for the southwest monsoon to advance further into Maharashtra, Telangana, Odisha, Jharkhand, Bihar and Chhattisgarh around June 23.
Recent rainfall in Mumbai and expanding cloud cover over central India suggest that monsoon activity is likely to intensify over the coming days.
The IMD has also forecast rainfall across Madhya Pradesh, Vidarbha and Chhattisgarh between June 21 and 26.
El Niño May Affect Seasonal Rainfall
Meteorologists have cautioned that El Niño conditions could reduce monsoon rainfall this year.
Bihar receives an average seasonal rainfall of 991.7 mm during the monsoon. However, experts warn that precipitation may remain below normal.
El Niño is a global climate phenomenon characterised by unusually warm sea surface temperatures in the equatorial Pacific Ocean. It alters global wind patterns and can weaken monsoon circulation over India, leading to reduced rainfall.
National Rainfall Deficit Widens
The IMD declared the onset of the southwest monsoon over Kerala on June 4. However, between June 1 and 17, India recorded 48.5 mm of rainfall against the normal average of 80.6 mm, representing a deficit of nearly 38%.
Eastern states, including Bihar, Jharkhand, Odisha, West Bengal and the northeastern region, have reported rainfall deficits of up to 44%.
Maharashtra, which witnessed the monsoon’s arrival in southern regions on June 8, recorded a 78% rainfall deficit by June 17.
Agriculture at Risk
Experts warn that delayed monsoon rains could adversely affect paddy cultivation in Bihar, which is heavily dependent on seasonal rainfall.
Dr. M.D. Ojha, Chief Scientist at Bihar Agricultural University, Sabour, said delays in rainfall would impact nursery preparation and transplanting schedules.
“Paddy transplantation could be delayed by 10 to 20 days or even longer if rainfall remains inadequate,” he said.
Health Concerns Rise Amid Heatwave
The prolonged heatwave is also taking a toll on public health.
A senior physician in Patna, said excessive sweating caused by extreme heat can lead to dehydration and thickening of the blood, increasing the risk of brain strokes and cardiac arrests.
“We are seeing more cases of heat-related illnesses. Spoiled food due to high temperatures is also contributing to diarrhoea, dysentery and vomiting,” he said.
He added that many people are experiencing symptoms linked to electrolyte imbalance, including dizziness, muscle cramps and headaches, while fungal infections such as ringworm and skin rashes are also becoming more common.
