Extremely heavy rainfall across the Sikkim and Darjeeling hills and north Bengal foothills since Monday night has caused flooding and landslides that have damaged roads, houses and key bridges, paralysing life in the hills and plains.

Mud, rock and water running down the mountains damaged close to 400 houses in the Darjeeling and Kalimpong districts. At least three people, including two minor girls, were missing and tens of thousands were evacuated away from the swollen, fuming rivers. Hundreds of tourists got stranded.

A weather expert said a “sudden” low-pressure zone and southerly winds had caused 230mm of rain in 24 hours in Darjeeling, which was 68 times higher than the normal for this time of year.

The Balason river, which flows down the hills and cuts across the NH-31 at Matigara on Siliguri city’s northwest end, has damaged one of the pillars of the 50-year-old bridge that connects the city with Bagdogra airport.

With the tilted pillar causing a part of the bridge’s plank to subside, police are allowing only two-wheelers and pedestrians to cross the bridge.

Traffic has been stopped along NH-31, which runs along the “chicken’s neck” and connects the Northeast.

At Rangpokhola in Sikkim, a stream that flows along the Bengal border and cuts across NH-10 — the principal highway connecting Sikkim with the rest of the country — swept away two reinforcement pillars of its bridge on Tuesday night. The Sikkim government is allowing only light vehicles to ply — and only in a single flank — along the route, the most-used entry point to the state opposite the border town of Rangpo.

“Both bridges are strategically important for the region and the country, and are regularly used by the defence forces,” a retired army officer said.

“At Rangpo, the NHIDCL (National Highways and Infrastructure Development Corporation Limited) is building an alternative bridge that will be ready by the year-end. As for the bridge over the Balason, it’s surprising that neither the Centre nor the state has taken the initiative to build an alternative bridge so far.”

Swollen rivers

Principal rivers like the Teesta, Torsa and Jaldhaka have flooded their banks, with 70,000 people being shifted to safer places.

Tourist ordeal

Traffic has been affected across landslide-hit highways and roads, such as NH10 at 29th Mile and Swetijhora, creating a nightmare for thousands of local people and tourists travelling to Sikkim and Kalimpong from Siliguri or the other way round.

While some made detours with their vehicles, many were seen crossing the landslide spots on foot and then trying to hitch a ride. Many tourists missed flights, buses or trains because the travel to Siliguri had taken extra hours.

In the evening, North Bengal State Transport Corporation announced it would run three additional buses to Calcutta.

On Wednesday morning, a portion of NH55 — the main highway connecting Siliguri with Darjeeling along which the Darjeeling Himalayan Railway track runs — caved in at Cheuri Vhir near Mahanadi, halting traffic. “The Rohini Road and the Pankhabari Road are open and vehicles are moving between Siliguri and Darjeeling through these routes,” an official said.

The Khasimara primary school in Ghoramara island of South 24-Parganas caved into river Hooghly on Wednesday. The two-storey school had been one of the four primary education facilities on the island, with 55 students and three teachers. The state government had earlier decided to relocate the building. Report by Snehamoy Chakraborty, picture by Hedaytulla Purkait

Missing

A portion of Vauxhall, the official residence of the sub-divisional officer (SDO) of Darjeeling, took a landslide hit on Tuesday night. D. Roy, the SDO, was not at home at the time. Suman Thapa, 59, a policeman posted on the compound, is missing. A search is on.

In Alipurduar, two minor girls who had gone to the Torsa’s banks are missing.

Low pressure

Weather experts said it rarely rains in north Bengal this time of the year. “Data shows there’s hardly any rainfall at this time as the southwest monsoon starts withdrawing from September-end. But this rain was caused by a sudden low-pressure area that developed in the region, along with southerly winds,” a meteorologist said.

He said the average rainfall in Darjeeling on October 20 is 3.2mm. “But it rained around 230mm (from October 19 morning to October 20 morning), which is over 68 times the normal,” he said.