Dehradun (PTI): The search operation to trace four missing labourers at the site of an avalanche-hit BRO camp in Mana village of Uttarakhand's Chamoli district resumed on Sunday with the help of sniffer dogs and helicopters.

Chamoli District Magistrate Sandeep Tiwari said the search operation is expected to gain pace as the weather is clear and a ground penetrating radar (GPR) system from Delhi is expected to arrive here any moment to aid the efforts.

An Mi-17 helicopter is waiting in Dehradun to fly the GPR system to the avalanche site, he said.

The avalanche hit the Border Roads Organisation (BRO) camp between Mana and Badrinath on Friday, burying 55 workers inside eight containers and a shed, the Army said.

The number of avalanche-hit labourers has been revised now from 55 to 54 as one of them from Himachal Pradesh, who was on unauthorised leave without telling his employers, has reached home safely.

Fifty labourers were pulled out of snow by Friday out of which four are dead.

Tiwari said the operation now is focused on tracing the missing workers and evacuating the workers still stranded.

State Disaster Response Force (SDRF) and National Disaster Response Force (NDRF) teams with a sniffer dogs have arrived at the avalanche site to help in the search and rescue efforts, he said.

Lt Gen Anindya Sengupta, GOC-in C, Central Command, and Lt Gen D G Mishra, GOC, Uttar Bharat, have reached the avalanche site to monitor the rescue operations.

Six helicopters -- three of the Indian Army Aviation Corps, two of the Indian Air Force (IAF) and a civil chopper hired by the Army -- have been engaged in the operation.

Located three kilometres from Badrinath, Mana is the last village on the India-Tibet border at a height of 3,200 metres.

The four labourers still missing are Harmesh Chand from Himachal Pradesh, Ashok from Uttar Pradesh and Anil Kumar and Arvind Singh from Uttarakhand, it added.

Army officials said the rescue operation on Saturday was mostly carried out by the Army and IAF helicopters as the approach road was blocked by snow at several points, making vehicular movement nearly impossible.

The priority is to bring the rescued workers to the Army hospital in Jyotirmath and look for the four missing workers, they said.

If weather permits, specialised RECCO radars, unmanned aerial vehicles (UAVs), quadcopters and avalanche rescue dogs will be pressed into service to trace the missing workers, Lt Gen. Sengupta said.

"Everything depends on the weather," he added.

More than 200 personnel from the disaster management authority, ITBP, BRO, NDRF, SDRF, IAF, district administration, health department and fire brigade are engaged in the rescue operations, he said.