The threat of a lake burst in Tibet portending a catastrophic flood in Himachal Pradesh has exposed India's vulnerability to environmental warfare where nature's forces are manipulated to create deadly weapons, a senior defence official has said.

Also Read Why are 10,000 Himachalis confused? The mysterious Tibetan Lake

The unfolding drama in the Himalayas has also, for the second time, punched holes in India's satellite surveillance system despite the country having a fleet of remote sensing satellites.

The SSS first came under criticism during the Kargil war for its inability to spot Pakistani movements. In the present case, Indian government woke up only after a warning from China on August 11.

Indians do not know what is blocking the Pareechu river that has created the artificial lake, but China has said rocks from a natural landslide caused the blockage.

"This may very well be true, but whatever the cause, the lake burst offers China a test case to study the effect of this new kind of environmental weapon - a lake bomb," the defence scientist told PTI on condition of anonymity.

Denial of permission for Indians to visit the site, conflicting information from China about the lake parameters, and the Chinese warning to India a month after the supposed "landslide", heighten suspicion that the impending lake burst is being treated as an experiment, the scientist said.

Analysis of the archived imageries of the region by Indian defence scientists has shown that the place, which is a lake now, was a catchment area from where water used to flow freely.

This area has turned into a reservoir threatening to break through the rock barrier. P Perumal, a hydrologist at the Indian Institute of Technology in Roorkee, said the lake burst would have horrific effects, as water is likely to rush down the hilly slope through a narrow gorge.

"It will not be like floods in the plains where water can spread out," he said on telephone. "What one can expect is a huge wall of water moving in bulk without its height getting diminished."

Its weight, combined with gravitational pull (Himachal is below Tibet), will flatten everything on the route for several kilometers in just a few hours, he added.

According to defence analysts, danger posed by the lake in Tibet is just the tip of the iceberg. India's geographical location at the foot of the Himalayas makes it vulnerable to "environmental attacks" from the numerous glaciers precariously perched atop the mountain range.

These mountains of ice can be "toppled" by remote triggering with explosives or their melting accelerated by covering them with carbon black to enable them to absorb more sunlight.  This could result in flooding of the Gangetic plains, the scientist said.

The analysts said Chinese scientists had been extensively mapping the Himalayan glaciers for nearly three decades with the help from the International Center for Integrated Mountain Development in Katmandhu.

Over 46,000 highland glaciers exist in Asia, most of them in the Himalayas, and the Qinghai-Tibet Plateau Research Institute under the Chinese Academy of Sciences is dedicated to glacier studies.

Officials of the National Remote Sensing Agency in Hyderabad, however, denied allegations that they "goofed up."

Responding to a question why India was not forewarned by its own scientists,  NRSA director R R Navalgund, told PTI: "NRSA provided relevant information/images to the concerned authorities in the second fortnight of July itself" before the alert from China.

Navalgund did not name the agencies that received this piece of intelligence, but Science and Technology Secretary Valangiman Ramamurthi said he did not know about NRSA's warning.

He, however, said the information was perhaps given to other agencies.

India has numerous disaster mitigation units functioning under different ministries including agriculture, water resources and science and technology, not to speak of the newly set National Disaster Mitigation Center in New Delhi.

NRSA's imageries taken in July should have alarmed at least one of these agencies.

Sources in NRSA told PTI that the agency should not be blamed even if it had overlooked the crucial satellite imageries.

"NRSA cannot and does not process every image it gets from the satellites. It is the job of the user agencies," they said, adding that NRSA does not normally look at imageries outside India's borders.

Manoj Datta, a professor of civil engineering at the Indian Institute of Technology, Delhi, said technology options -- such as tunneling through rocks or sending divers to carry out controlled blasting to open an exit for water -- are available to prevent a disaster of this kind.

Kapil Gupta, professor of water resources engineering at IIT, Mumbai, believes that a joint Indo-Chinese strategy in the
early phase could have averted the event from reaching the crisis stage.

"There is expertise in India in the academic institutions and in the defence department but we cannot offer any solution without knowing the geology of the place or the actual nature of the rock material blocking the river. So the only option
for us is to move the people."

Datta, however, cautioned that even if the artificial wall that this holding the lake water survived the current rainy season, its long-term stability is not assured.

"In any case, whatever is blocking the  river must ultimately be removed because otherwise water supply to the Sutlej river may get reduced," Gupta added.