Bihar remains under unsettled weather conditions on Friday, September 25, with the India Meteorological Department issuing a yellow alert for rain in 19 districts as thunderstorms, lightning and strong winds remain possible. At the same time, authorities are closely monitoring the Kosi River after heavy rainfall in Nepal raised concerns that discharge from the Kosi Barrage could climb to between 5 lakh and 6 lakh cusecs.
The combination of continued rainfall, storm activity and rising river levels has increased concern in vulnerable parts of the state, particularly communities located within or close to embankments.
IMD Issues Yellow Alert for 19 Bihar Districts
The IMD’s Patna Meteorological Centre has warned of heavy rain, thunderstorms and lightning in Bihar on September 25, with similar weather hazards continuing into September 26.
A yellow alert has been issued for 19 districts for Friday, while other parts of Bihar are expected to experience comparatively less intense conditions.
The weather department has warned that thunderstorms could be accompanied by lightning and strong winds. People have been advised to remain cautious during storm activity, particularly in open areas and near trees or weak structures.
Rain has already been reported across several parts of the state over the past 24 hours, including Patna and other districts.
Kosi River Level Could Rise After Heavy Rain in Nepal
The bigger concern is developing around the Kosi River, where inflows may increase because of heavy rainfall in neighbouring Nepal.
Officials have warned that discharge from the Kosi Barrage could rise to approximately 5 lakh to 6 lakh cusecs, prompting the Bihar Water Resources Department to increase monitoring.
Engineers and local authorities have been asked to remain alert as the higher volume of water moves downstream.
Residents living inside embankments or in low-lying areas have also been advised to be prepared to shift to higher ground if the situation worsens.
Public announcements are being used in vulnerable areas to warn communities about the possible increase in river levels.
Saharsa Areas Asked to Remain Alert
Authorities have specifically urged residents in parts of Nauhatta, Mahishi, Simri Bakhtiyarpur and Salkhua blocks of Saharsa district to take precautions.
People in locations vulnerable to Kosi flooding have been advised to identify safer and elevated areas in case evacuation becomes necessary.
Boat operators have also been placed on alert as officials prepare for the possibility of a rapid increase in water levels.
The Kosi has historically posed a major flood risk to northern Bihar, making sudden increases in upstream discharge especially important for local disaster-management authorities.
Heavy Rain and Winds Disrupt Life in Several Districts
Friday’s alert follows another spell of rain and storms across Bihar.
In Patna district, strong winds and rain uprooted a large tamarind tree in Dargahi Tola under Pandarak police station limits. The tree fell onto National Highway 31, disrupting traffic.
Significant rainfall was also recorded in several districts during the previous 24 hours.
Khagaria recorded around 74 mm of rain, Katihar about 67 mm, Banka approximately 65 mm, while Patna and Munger each received about 62 mm, according to weather data cited in local reports.
Samastipur recorded about 39 mm of rain, accompanied by strong easterly winds.
Weather-Related Deaths Reported
The latest spell of bad weather has also been linked to fatalities.
Three students were reported killed after a tree fell in Samastipur, while a woman died after a wall collapsed in Banka during heavy rain.
Such incidents underline the risks associated not only with flooding but also with lightning, falling trees, damaged buildings and strong winds during severe weather.
Residents have been advised to avoid sheltering beneath trees during thunderstorms and to stay away from structures that may have been weakened by persistent rain.
Why Bihar Is Seeing Continued Rain
Several weather systems are contributing to the unsettled conditions.
The southwest monsoon has started withdrawing from parts of northwestern India, but it remains active over Bihar.
At the same time, a deep depression that developed over the north coastal Andhra Pradesh region has been moving northwest and weakening gradually. An upper-air western disturbance has also been influencing regional weather patterns.
Together, these systems are supplying moisture and creating atmospheric instability, supporting continued rainfall and thunderstorms across Bihar.
The IMD’s September 25 warning indicates heavy rain and thunderstorm activity for Friday and Saturday before conditions are expected to improve further into the forecast period.
Bihar Still Faces a Significant Monsoon Rainfall Deficit
Despite the current rain spell and recent flooding in several areas, Bihar remains significantly below its normal seasonal rainfall total.
As of September 24, the state had received approximately 612 mm of rainfall against an expected 949.4 mm, representing a deficit of about 36%, according to weather-department figures cited in the latest report.
This creates an unusual situation in which individual districts and river basins may face flood or waterlogging threats even while the state’s overall seasonal rainfall remains below normal.
Rainfall in upstream catchments outside Bihar, particularly in Nepal, can also push river levels higher regardless of the statewide rainfall deficit.
Rising Rivers Remain a Broader Concern
Bihar has already dealt with serious flooding earlier in September.
More than 40 lakh people across 14 districts were reported affected during an earlier flood spell when several rivers crossed danger levels following heavy rainfall in Bihar and upstream areas.
The Ganga, Kosi, Gandak and other rivers have been closely monitored through the monsoon season, particularly in flood-prone districts.
The latest Kosi warning therefore comes against a backdrop of already saturated or vulnerable areas in parts of the state.
Key Facts
Alert level: Yellow alert in 19 Bihar districts
Date: September 25, 2026
Main hazards: Rain, thunderstorms, lightning and strong winds
Kosi concern: Barrage discharge could reach 5-6 lakh cusecs
Areas on special alert: Parts of Saharsa district including Nauhatta, Mahishi, Simri Bakhtiyarpur and Salkhua
Recent rainfall: Khagaria 74 mm, Katihar 67 mm, Banka 65 mm, Patna and Munger around 62 mm
Seasonal rainfall deficit: About 36% as of September 24
What Happens Next?
Weather authorities expect rain and storm activity to remain possible across Bihar over the next two days, while conditions should gradually become less widespread afterwards.
The most immediate concern will be the movement of water through the Kosi system.
Authorities are expected to continue monitoring barrage discharge, embankments and vulnerable settlements. Residents in low-lying and riverbank areas should follow district administration and disaster-management advisories, particularly if evacuation instructions are issued.
FAQs
How many Bihar districts are under yellow alert?
A yellow alert for rain and thunderstorms has been issued for 19 districts on September 25, 2026.
Why is the Kosi River a concern today?
Heavy rainfall in Nepal may increase Kosi inflows, with officials warning that discharge from the Kosi Barrage could reach between 5 lakh and 6 lakh cusecs.
Will it rain in Patna today?
Yes. Cloudy conditions and intermittent rain are expected in Patna, with thunderstorms possible in some areas.
Which Bihar areas have been asked to remain especially alert?
Residents in parts of Nauhatta, Mahishi, Simri Bakhtiyarpur and Salkhua blocks in Saharsa district have been advised to remain cautious because of the possible rise in the Kosi.
How much rainfall deficit does Bihar have?
As of September 24, Bihar had received about 612 mm against an expected 949.4 mm, leaving the state with a seasonal rainfall deficit of roughly 36%.