Torrential rain continued to batter North Bengal on Friday, washing away a temporary bridge over the Balason River at Dudhia, triggering landslides along key highways and disrupting connectivity between Siliguri, Mirik and Darjeeling.
Authorities have diverted traffic through alternative routes, suspended toy train services and launched restoration efforts as rivers across the region remain in spate.
Heavy overnight rainfall, estimated at nearly 200 mm across parts of the hills and adjoining plains, caused a sharp rise in river levels and widespread infrastructure damage.
One of the worst-hit locations was Dudhia in Darjeeling district, where a temporary hume pipe bridge over the Balason River collapsed after water levels surged due to incessant rain.
"A portion of the temporary hume pipe bridge at Dudhia collapsed after a sudden rise in water level of the river due to incessant rain," an official told PTI.
The temporary structure had been built after the original Dudhia iron bridge was washed away during floods in October last year.
Following the collapse, direct road connectivity between Siliguri and Mirik has been cut off. Travellers have been advised to use alternative routes through Patong-Panighata or via Sukhiapokhri-Ghum and Pankhabari. The tourist destination of Rangbang-Tabakoshi near Mirik has also been cut off after another temporary bridge was washed away.
Vehicular movement has additionally been affected by landslides at Tindharia and Paglajhora, forcing the closure of the Siliguri-Kurseong stretch of National Highway 110. However, the Kurseong-Darjeeling section of the highway remains open. Rohini Road, Pankhabari Road, Peshok Road and routes connecting Siliguri with Kalimpong remain operational.
The disruption has impacted the Darjeeling Himalayan Railway as well, with all toy train services scheduled for Friday being cancelled. Railway authorities said services on the Darjeeling-Kurseong route may resume from Saturday, subject to weather and track conditions.
The Central Water Commission, in its flood forecast on X, said, "The old Dudhia Bridge was washed away during a flash flood in October last year. Due to high river flow and ongoing erosion, the newly under-construction bridge (on the way to Mirik Route) at the same site is also under threat."
The India Meteorological Department (IMD) issued a red alert for heavy to very heavy rainfall, with extremely heavy showers likely in parts of Jalpaiguri and Alipurduar districts over the next few days.
An orange alert was issued for Darjeeling, Kalimpong and Cooch Behar districts, forecasting heavy to very heavy rain accompanied by thunderstorms and gusty winds.
An orange alert was also issued by the Met office for south Bengal districts of Kolkata, North and South 24 Parganas, Purba Barhaman, Purba and Paschim Medinipur districts for the next 48 hours.
The situation worsened on Thursday night after rapidly rising river levels prompted authorities to open the gates of the Mahananda Barrage at Fulbari. Water levels in the Teesta and other rivers are also being monitored round the clock amid concerns of further flooding.
Darjeeling MP Raju Bista visited the affected site and blamed the state government for the recurring connectivity crisis.
"The TMC government had not been able to construct a permanent structure after the iron bridge collapse. The temporary bridge was poorly constructed and was bound to face such problems during heavy rain," the BJP MP told reporters.
He said a Bailey bridge built with the assistance of the Border Roads Organisation or the Army would have provided a more durable interim solution.
Bista also said the public works department was constructing the approach road and related infrastructure for a permanent bridge project. Stressing the need for a long-term solution, he said, "A detailed project report for a dam has already been prepared and sent to Jadavpur University for technical review. Once the monsoon season is over, work on the dam will begin. That is the only long-term solution to this problem."
Public works department minister Ajay Kumar Poddar said restoration work would begin once river levels recede. "Restoration work will begin on a war footing once the river water level recedes," said Poddar, adding that a special engineering team has already been deployed at the Dudhia site.
He said construction of a permanent bridge at Dudhia, estimated to cost around Rs 52 crore, is underway and is expected to be completed by February 2027. Officials said the state government has sanctioned more than Rs 51 crore for the permanent two-lane bridge project.
Weather experts have warned that dense cloud formations over Bhutan and Sikkim could trigger further heavy rainfall in the coming days, raising the risk of fresh landslides, river swelling and flooding in the Dooars and adjoining plains.
Locals said the collapse of the temporary bridge would affect daily commuting and transportation of essential goods in the area until emergency restoration measures are undertaken.