Dehradun, Jan. 15 -- The forest fire raging for the past six days near the UNESCO World Heritage site, Valley of Flowers in Chamoli district, remains confined to the surface and is not very extensive, senior forest officials said on Wednesday, following an aerial survey of the affected site. The fire erupted in the forests of Painkhanda under the Valley of Flowers range of Nanda Devi National Park at an altitude of around 11,500 feet on January 9. Difficult terrain and lack of access routes prevent teams from reaching the area on foot, rendering manual firefighting ineffective, officials said. Sushant Patnaik, chief conservator of forests and state nodal officer for forest fires, said, "An aerial survey of the fire-affected site on Wednesday revealed the fire spots. Prima facie, the fire appears not to be very extensive or serious. It is in small pockets, possibly due to the burning of leftover stumps. It is limited to the surface and hasn't reached the crown. It is not a total burning of forests. It is a surface fire at various locations, but due to the inaccessibility of the site, our staff cannot douse it." Patnaik said based on the field report and aerial survey, the forest department will take further action, including whether to seek help from the Centre. Forest minister Subodh Uniyal has directed senior officials to investigate the possible causes of the Chamoli fire. In a letter to disaster management secretary Vinod Kumar Suman, Chamoli district magistrate Gaurav Kumar reported that personnel at the Auli wireless station within Nanda Devi Forest Division spotted smoke near the Alaknanda River, opposite Govindghat, on January 9 at 10.10am. "Responding to this, the Range Fire Control Team was immediately dispatched to prevent and control the forest fire," the letter said. Two separate teams were sent. While the first one crossed the Alaknanda River from Govindghat and headed directly to the scene, the second team was sent from Pulna village to accurately assess the extent and geographical location of the forest fire through a drone. The team at the scene reported extremely difficult terrain with steep rocks, dry grass, and heavy frost, making surfaces slippery and inaccessible. Steep slopes make it impossible and life-threatening for personnel to reach the fire on foot. Efforts on January 10 and 11 failed to control it. Extinguishing the fire manually is impossible and fatal for employees, the letter added. Dry weather, inaccessibility, and strong winds could spread it widely, threatening forest wealth and wildlife. The letter urged monitoring via Air Force or disaster management helicopters for water sprinkling if needed. Uttarakhand disaster management secretary Vinod Kumar Suman confirmed on Tuesday that they requested Indian Air Force support....