Bharat Mohanty, a 34-year-old resident of Rangpo in Pakyong district of Sikkim, warns anyone heading towards a large vacant land along the banks of the river Teesta: “Don’t go there. There may be explosives underneath the silt.”

Read here: ‘Darkness and chaos’: Sikkim flood victims share ordeal; rescue op halted

Local residents in the flash flood-ravaged Rangpo in East Sikkim pointed to what appeared to be a playground, but it was in fact a slum comprising dozens of houses until a few days back. The slum was surrounded by multiple four-to-five storey buildings on three sides, with the Teesta flowing on the fourth.

“The slum is now buried under 10-12 feet of silt and debris brought in by the flood waters. The muddy water and debris also gushed into the ground floors the adjoining buildings,” Mohanty, who lived in the ground floor of one of those buildings, said.

Now, the entire colony plunges into darkness at night as there is no power supply since the flood hit the area in the early hours on Wednesday. Mobile connectivity has also been affected.

A few cars and an earth-moving machine, buried under the silt with just their roofs visible, gave an inkling of what was underneath the debris.

It was around 2am on Wednesday that Sidhant Chetri (23), another resident of IBM colony, as the area is popularly called, heard some frantic whistles and screams.

“I just woke up and sat on my bed. Somebody banged on my door. As soon as I got down from the bed, there was ankle-deep water in my room. More water was seeping inside. A neighbour informed that a flood has hit the area. I woke up my roommate and rushed out to a road on the higher elevation. Within minutes the floodwaters covered everything,” Chetri recalled.

Around 1.30 am on Wednesday, a glacial lake outburst flood triggered by torrential rain slammed into the Chungthang dam, cleaving the structure and barrelling downhill where it left villages and towns buried under silt and debris. So far, the known number of casualties stood at 55 while at least 143 remain missing, according to officials. More than 40,000 people have been affected.

Mangan in north Sikkim and Pakyong in the east were the two worst-hit districts in the northeastern state. Of the total casualties in the devastation, 19 people, including nine army personnel, died in Pakyong alone while 38 remain missing.

The Sikkim government has warned people that explosives might be found along the banks of Teesta as an ammunition depot of the army in north Sikkim was also affected in the flash floods. At least three people were killed in neighbouring West Bengal when they tried to handle the explosives deposited on the river’s bank.

“Earlier this morning some army personnel came and defused a mortar that was found around 2 km upstream,” Mohanty said.

In Mangan district, a team of the disaster response force in Sikkim finally managed to reach Chungthang, which had remained cut off from the rest of the northeastern state since Wednesday.

“While the first team of SDRF personnel managed to reach Chungthang on Friday night, a second team reached this [Saturday] morning. Nearly 80% of the town has been damaged and most of the houses, shops and offices are buried under several feet of debris,” a top government official said.

The SDRF team had to trek for several kilometres through treacherous hilly trails and then cross the Teesta using a precarious suspension bridge to reach the town.

“There are no reports of any casualties from the town till now. Relief has finally reached Chunthang. We hope to restore communication lines within two to three days,” a senior IAS officer posted in Mangan said.

Air-borne rescue operations could not be started even on Saturday due to bad weather conditions in the hills. At least three Mi-17 choppers are kept on standby in Bagdogra and Lachen.

Read here: Inter-ministerial team to visit flood-hit Sikkim from Sunday to assess damages

The Sikkim government has opened alternate routes for stranded people, including tourists, to reach West Bengal, to take trains and flights. The National Highway-10, which formed the lifeline of the Himalayan state, has been washed away in the floods at multiple places.

“My wife, daughter and I were stuck at Rangpo for three days. We had to put up in a hotel at a higher elevation after our house got inundated by the floodwaters. That night was traumatic,” Dinesh Chakraborty, an employee of a private firm who was working on a railway project in east Sikkim, said. “Finally, we made it.”

Normally it takes two to three hours to reach Siliguri in north Bengal from Ranpo via NH-10, the alternative route through Lava and Gorubathan is taking double the time.