Most of the monsoon clouds reaching the Lachung valley precipitate before Yumthang but those venturing further north towards the Tibetan plateau have to encounter the last bastion in the valley- the Donkiala pass at 18400 ft. Overlooking the Cholamu plateau and the Roof of the World, and surrounded by snowy peaks most notably the Paunhri (LonpoKyangzong), the Donkia pass is like a nozzle that feebly sprays the plateau with whatever moisture remains in the spent monsoon clouds.
Similarly, mortals wanting to cross over from the Lachung valley to the Cholamu plateau have to encounter the Donkia pass and once they have done it they are depleted of energy and it takes them quite some time to get their breath back. Donkialapass separates the upper reaches of Lachen valley from the Lachung valley and Hooker in his book “The Himalayan Journal” has rated it the most treacherous pass he ever traversed.
The motorable road ends thirty kilometres away from Yumthang via YumeySamdong at a place called Zadong-at an altitude of about 16030 ft. We disembark from the vehicle and ask the driver to reach Cholamu via Lachen by the next day to receive us. From here to Cholamu Lake via the Donkiala pass is about an 8 kilometres trek and takes 5 to 6 hours for the average walker. We start walking along the narrow Donkiachuriver.
The climb is moderate but the progress is relatively slow because of rarefied air. The hillside is carpeted with alpine vegetation in a riot of colours – aconite, the rare blue poppies and a lot of other colourful flowers – I wish I could identify them. And dominating them like sentinels, are the yellow giant rhubarbs growing to about three feet in height.
After walking for 2 hours, the Donkiala pass becomes visible. It looks quite near but takes a full hour to reach. We come across two small muddy lakes from which the river Donkiachu originates and flows into the Lachung valley. Glacial lakes look deceptively calm but are in a state of continuous flux and excessive melting of the glacier can cause them to burst their banks wreaking immense damage downstream- a phenomenon known as Glacial Lake Outburst Flooding (GLOF). A few years ago the glacial Tenbawa lake close by burst causing flash floods in the Yumthang and Lachung valleys.
A wall of water that gushed down, washed away bridges and caused a lot of damage to property. There is a need to monitor these lakes on a continuous basis through Satellite imagery and Synthetic Aperture Radar (SAR): any change in their size would be a signal for imminent disaster.
The last stretch of 100 metres to Donkiala pass is very steep and involves almost a vertical climb. Our bodies suddenly seem to weigh more than a ton and our legs almost crumble as the stress caused by rarefied air begins to take effect. Gasping and panting for air and feeling like a fish out of water, we finally reach the pass. But all our tiredness vanishes at the sight of the spectacular scenery around us. Above the Donkiala pass, spires of peaks rise their gloomy granite brightened by snow.
The peak of Pauhunri (LonpoKyangzong) is silhouetted against the eastern sky. The relatively low altitude Chola range that delineates the eastern border of Sikkim suddenly soars up in the North to Pauhunri – the highest peak on the Eastern border of Sikkim – its ramparts scarred with many glaciers. From the Donkia La pass the view of the Tibetan plateau and its portion that juts into Sikkim as the Cholamu Plateau below us is marvellous. The plateau is flat as far as the eye can see but is broken here and there by small hillocks peppered with snow.
Through powerful binoculars, we can see the habitations at Tarksing and Geru on the Tibetan side. About 300 metres below is the lake of Cholamu and a smaller un-named lake above it. -both looking like emeralds. Slightly towards the west Tista meanders and breaks into many channels enclosing small oases of green vegetation sustaining wildlife and yaks on the plateau.
As we stand marvelling at the scenery below it begins raining heavily in the Lachung valley, whereas above and over the Tibetan plateau in sharp contrast it remains bright and sunny. I had read in books about how the high mountains of North Sikkim prevented moisture-laden clouds from reaching the dry and arid plateau, but here I was seeing it actually happening before me.
A knee-wobbling downhill walk of another hour and a half takes us to Cholamu lake. The reflection of the surrounding mountains doubles its beauty. Now, about the source of the Tista. Many consider Cholamu as the Source of the Tista. This is not true. The source of a river is defined as the farthest point from where a river starts flowing. Cholamu is one of the lakes in the river system that flows out as a stream to meet the Tista just a few hundred metres away. After walking the full length of the Cholamulake we turn right and cross Tista and reach the Army Camp at Kerang.
A cup of hot tea with the jawans and rest of about an hour and we move onwards to explore the source of Tista. We walk for about slightly over an hour on the gently undulating land and are at the edge of a glacial lake. On the other side of the lake on the western base of the Paunhri is the Glacier – TistaKhanste which melts to form KhangchungTso lake. Chunks of ice break away from the glacier – mini icebergs- float in the lake – tethering between the solid and liquid states and then slowly melting away. It is from this lake the mighty Tista river takes birth as a trickle hardly a metre wide – the feeble beginning notes of which transform to a thunder few kilometres downstream- a river that tumbles and turns and trips over itself – its flow now being tempered downstream by the hydroelectric projects.
The plateau preserves an astonishing diversity of wildlife. A flock of birds that look like cranes swim on the placid ice-cold water. These birds are migratory probably coming from the northern latitudes. It strikes me that no natural or manmade borders are impregnable to these birds. Russia, China, and India are to them one and the same – they believe in the true spirit of globalisation.
It is a pity that a man with a penchant for divisions cannot move freely from one place to another. A herd of Tibetan wild asses or kiangs as they are locally called, stand grazing on the other end of the lake. As there is a dearth of water on the Tibetan side, many animals cross over the border towards the lake. The plateau is teeming with marmots (big mice), woolly hares and foxes. Once in a while, a flock of snow flinches(birds) fly overhead.
Although deprived of any vegetation except sparsely growing scrubs, the plateau offers a stark beauty unparalleled perhaps anywhere in the world. The landscape here is similar to the fiery desert while the climate is that of the Tundras. Temperatures can rise to above 20 degrees Celcius or drop below minus 20 degrees within a matter of hours: you can therefore get a sunburn because of the intense sunlight or frostbite because of the intense cold.
The precipitation received by the plateau is less than 50 cm in a year as compared to Gangtok’s 325 cm. Violent winds rage their force broken by neither trees nor scrubs. Howling with such ferocity, these winds also sweep snow from the grass uncovering it for the yaks. The air is so rarefied and clear that the stars literally choke the sky and shine bright enough in the moonless sky to cast faint shadows and cause the snowclad mountains around to glisten eerily.
The intense sunlight and the high-speed winds that the plateau experiences can be a good source of solar and wind energy. The use of solar panels and wind generators can easily meet the energy needs of the few hundred people who reside here.
Herds of yaks graze on the sparse vegetation and the few herders here make their livelihood by selling yak products. These herders follow lifestyles unchanged through the centuries: the pastoral herding scene appears to have evolved very little. For us, a visit to this area is an adventure but for the yak herders, it is just another day at the office. For hard work and acceptance of nature’s sway, this moody and elemental place offers the herders in return the splendour of scenery.
For a man from the city, staying in such a hostile environment would be unthinkable. But wouldn’t a yak herder also find the city hostile, with its high decibel earsplitting noises and pollution that makes the air almost unbreathable? Such contemporary troubles like nuclear explosions and the depletion of the ozone layer seem deceptively far away. But these herdsmen have been affected apparently in terms of increased Ultraviolet radiation and acid rain because of the avarice of their urban brothers.
In the most inhospitable places, there is a wealth of hospitality. At a stone hut of the yak herder near Cholamu over a glass of hot Tibetan tea, which is a concoction of fermented tea leaves, yak butter and salt, I was told by one that the furthermost most of them had ventured was Thangu barely 30 kilometres away. Suddenly I start envying them for their lifestyles, which seem an anachronism in this modern age and have remained unchanged for centuries and untouched by the ravages of civilization.
Later I am told that the yak herder headman had been chosen for the post because he had the distinction of having visited Siliguri – for about a few months for medical treatment – and therefore considered as a person well exposed and wise with the ways of the world.
An abandoned yak herders hut testifies to the changing times. The kids simply do not want to become yak herders any more. Instead, they aspire to land safer, salaried jobs in urban areas thus slowly and inexorably bringing down the curtains on a glorious way of life.