Yaye Tso Crater Lake: The Definitive Volcanic Caldera & High Pass Guide [2026]

Hidden deep within the arid, folded labyrinth of the eastern Ladakh Range lies one of the most enigmatic, visually stunning, and rarely visited bodies of water in the entire Trans-Himalayan wilderness: Yaye Tso (also written as Yaye Tso or Yaye Tso Crater Lake). Perched at an extraordinary altitude of 16,000 feet (4,877 meters) above mean sea level, Yaye Tso is situated in an isolated alpine amphitheater between the Indus River canyon at Mahe and the colossal, snow-capped barrier of Kaksang La (17,841 feet). What immediately arrests the attention of geologists, mountaineers, and intrepid motorcycle explorers upon cresting the barren crater rim is the lake's radical divergence from every other body of water in Ladakh. While Pangong Tso and Tso Moriri are famous for their crystalline shades of cobalt, navy, and turquoise, Yaye Tso gleams with an intense, otherworldly emerald green hue, glowing like a polished jade gemstone set within a stark, dark amphitheater of volcanic basalt, andesite, and fractured purple shale. The geological origin of Yaye Tso has long been a subject of intense scientific fascination across the Geological Survey of India and the Wadia Institute of Himalayan Geology. While popular local lore frequently describes the lake as a volcanic crater lake, geologists clarify that it represents a composite volcanic-tectonic caldera depression. Millennia ago, during the violent tectonic collision between the Indian continental plate and the Eurasian plate along the Indus Suture Zone (ISZ), intense localized magmatic upwelling and volcanic outpourings produced thick deposits of basaltic lava, volcanic tuffs, and pyroclastic breccia across this sector of the Ladakh batholith. Subsequent subterranean magma chamber collapse, combined with severe Quaternary glacial scouring, carved out a deep, enclosed circular caldera bowl. Today, the basin is filled with dense mineral-rich water fed by sub-surface geothermal springs and high-altitude glacial permafrost seepage. The remarkable emerald-green color of the water is the direct optical result of high concentrations of dissolved copper, sulfur, and volcanic mineral salts interacting with intense high-altitude ultraviolet radiation. Because Yaye Tso occupies an enclosed, bowl-shaped crater depression without any surface river outflow, it behaves as an alpine endorheic basin. The water level fluctuates purely in response to seasonal glacial snowmelt inflows from June through August and intense solar evaporation driven by the ferocious, dry Trans-Himalayan winds. Around the perimeter of the lake, rings of white mineral precipitates mark former high-water levels, creating a startling visual contrast against the dark, crumbling volcanic talus slopes that rise hundreds of meters above the shoreline. To the local Changpa nomads and the Buddhist villagers of Rong, Yaye Tso is revered as a sacred spiritual sanctuary, believed to be the dwelling place of powerful water spirits (Lu or Naga) who protect the high mountain passes from destructive storms.

The overland expedition to Yaye Tso represents one of the most demanding, technical, and remote adventure routes in Ladakh, testing both rider endurance and vehicle mechanical capability. The journey begins along the classic Southern Trans-Himalayan highway connecting Leh to the Indus Valley via Upshi (48 km) and Chumathang (138 km). Upon reaching the strategic military bridge at Mahe (163 km from Leh, 13,800 feet), travelers must present their Inner Line Permits at the Indo-Tibetan Border Police (ITBP) checkpost. While standard tourist traffic crosses Mahe Bridge and heads south toward Sumdo and Tso Moriri, the expedition to Yaye Tso requires crossing the bridge and immediately watching for an unpaved, unmarked dirt fork heading northward into the rugged side canyon of Rong. Leaving the paved Indus highway behind, you enter a stark, sun-scorched granite gorge flanked by towering cliffs of banded gneiss and volcanic rock. The initial seven kilometers track a narrow, broken tarmac lane that leads to the tiny, isolated hamlet of Rong (14,100 feet). Rong is the absolute last permanent human settlement along this entire corridor; beyond its modest stone houses, prayer walls, and small willow groves, all signs of modern infrastructure cease completely. There are no power lines, no commercial shops, no fuel pumps, and no mobile cellular reception of any kind. From Rong onwards, the road degrades into a raw, single-lane dirt track carved directly into the shifting moraine scree by the Border Roads Organisation (Project Himank). The ascent from Rong toward Yaye Tso is relentless. Over the course of the next 15 kilometers, the track climbs nearly 2,000 vertical feet across a series of steep, unpaved switchbacks characterized by loose shale, deep gravel washes, and exposed boulder steps. Gradients frequently exceed 14 to 18 percent, demanding aggressive throttle control and steady momentum on adventure motorcycles, or low-range 4WD engagement in off-road vehicles. Riders must navigate around sharp rock fragments that threaten tire sidewalls, while avoiding the soft, deceptive gravel berms that accumulate along the unbanked outer edges of the cliff shelves. As you climb higher, the narrow canyon walls suddenly recede, opening into a high, windswept alpine bowl at 16,000 feet. Here, without any preliminary warning, the track skirts the crest of a massive moraine ridge, revealing the astonishing emerald expanse of Yaye Tso resting directly below. From this panoramic crater rim overlook, an unpaved trail descends down toward the lake's western shore. Continuing past Yaye Tso along this same wilderness trail leads travelers onto the even more formidable ascent of Kaksang La pass. Rising to a breathtaking summit elevation of 17,841 feet (5,438 meters), Kaksang La is one of the highest motorable mountain passes on earth, linking the Indus Valley directly to the remote frontier valley of Chushul and Mirpal Tso. However, crossing Kaksang La requires extreme mechanical preparedness, as the pass is frequently blocked by late summer snowdrifts and severe rockslides.

The unique geological formation of Yaye Tso cannot be understood without analyzing the complex plate tectonics of the Indus Suture Zone (ISZ) and the Ladakh Batholith. Approximately 50 to 60 million years ago, during the late Cretaceous and early Eocene epochs, the northward-drifting Indian tectonic plate collided with the southern margin of the Eurasian continental landmass, subducting the ancient Tethys oceanic lithosphere beneath the Asian continent. This monumental tectonic convergence generated extreme crustal thickening, deep partial melting of oceanic crust, and widespread calc-alkaline magmatism that formed the massive volcanic-plutonic arc of the Ladakh Range. Within the Kaksang mountain sector surrounding Yaye Tso, geologists have mapped distinct volcanic suites known as the Dras-Kargil volcanic group and the Shyok volcanics. Unlike the smooth, rounded granite tors common around Leh, the mountains flanking the trail to Yaye Tso consist of dark, jagged exposures of porphyritic basalt, basaltic andesite, and dacitic tuffs interspersed with purple volcaniclastic breccias. The circular depression of Yaye Tso itself represents an ancient volcanic collapse caldera. When deep sub-surface magma chambers emptied during explosive late-stage eruptions, the overlying volcanic dome lost structural support and collapsed inward along ring faults, creating an enclosed geological crater bowl. Subsequent tectonic uplift and Pleistocene glacial scouring heavily modified the caldera walls, steepening the inner slopes and blanketing the rim in sharp, angular talus scree. Because the volcanic rocks surrounding the lake contain high concentrations of hornblende, augite, iron oxides, and copper sulfide mineralizations, centuries of water-rock chemical interaction have leached heavy metallic ions into the standing lake water. Under direct solar radiation, dissolved copper and sulfur compounds absorb longer red and yellow light wavelengths while scattering shorter blue and green wavelengths, giving Yaye Tso its signature, radiant emerald jade coloration. The water is chemically dense, possessing high electrical conductivity and alkaline mineral content that prevents normal freshwater aquatic weeds from flourishing, maintaining absolute optical clarity across the lake surface.

Unlike the bustling shores of Pangong Tso or the established commercial homestays of Karzok at Tso Moriri, Yaye Tso remains one of the few places in Ladakh that offers complete, undisturbed wilderness solitude. On any given summer day, you are more likely to encounter a herd of wild mountain ungulates or an Indian Army high-altitude patrol than a civilian tourist vehicle. The absolute silence that blankets the Yaye Tso crater is broken only by the whistling of high-altitude crosswinds funneled through the mountain notches and the distant calls of alpine raptors circling overhead. Despite the harsh, volcanic terrain, the micro-ecosystem surrounding Yaye Tso supports remarkable high-altitude biodiversity. The lake's mineral-rich waters provide a nursery for specialized aquatic micro-invertebrates and cold-water algae, which thrive under the intense ultraviolet radiation of 16,000 feet. Around the northern and eastern shorelines, glacial meltwater streams create narrow strips of green alpine turf and sedge meadows. These isolated patches of vegetation serve as vital feeding grounds for pairs of Black-necked Cranes (Grus nigricollis) that arrive during their summer breeding season, taking advantage of the basin's total isolation to rear their chicks away from human disturbance. Other waterbirds frequently observed at Yaye Tso include Ruddy Shelducks (Tadorna ferruginea), Brown-headed Gulls, and occasional migrating waders resting on their Trans-Himalayan flyway journeys. On the craggy volcanic cliffs surrounding the crater, mammalian wildlife thrives in undisturbed security. Herds of Blue Sheep, or Bharal (Pseudois nayaur), graze precariously on near-vertical scree faces, their slate-gray coats rendering them virtually invisible against the basalt rock until they move. The abundance of marmots, pikas, and blue sheep makes the Yaye Tso basin a prime hunting territory for the apex predator of the high Himalayas, the elusive Snow Leopard (Panthera uncia). Local herders from Rong report regular winter and spring sightings of snow leopards traversing the crater rim. Golden Eagles (Aquila chrysaetos) and Lammergeiers (Bearded Vultures) with nine-foot wingspans ride the thermal updrafts created as warm air rises from the lower Indus canyon to meet the frigid mountain air of the Kaksang Range. For travelers, the complete absence of commercial development at Yaye Tso is both its greatest allure and its greatest challenge. There are no designated campsites, no pit toilets, and no food stalls. Visitors must practice strict 'Leave No Trace' ethics: carry out every scrap of rubbish back to Leh, refrain from washing dishes or vehicles with chemical soaps near the water, and never disturb the nesting sites of wild cranes. The pristine purity of Yaye Tso is a fragile ecological treasure that depends entirely on the conscious restraint and respect of every traveler who enters its volcanic gates.

Ascending the unpaved trail to Yaye Tso and the Kaksang Range places exceptional mechanical and thermal stress on every component of a motorcycle or four-wheel-drive vehicle. At 16,000 feet, the barometric pressure drops to roughly 410 mmHg, reducing atmospheric oxygen availability to approximately 52 percent of sea-level density. Combined with steep 18 percent gravel inclines, rough washboard corrugations, and high-altitude ambient cold, vehicle systems operate on the absolute margins of their engineering thresholds. On motorcycles, transmission and clutch systems bear the greatest brunt of the terrain. The steep, switchbacking climbs above Rong village require sustained operation in first and second gears. On heavily loaded adventure motorcycles, attempting to maintain speed over loose shale switchbacks often tempts riders to slip their clutches continuously. At 16,000 feet, where the cooling efficiency of the thin air is drastically reduced, prolonged clutch slippage causes rapid overheating of the clutch basket and friction plates. Within minutes, the clutch lever can lose its free play, leading to severe plate glazing, loss of drive, and complete immobilization on an isolated cliff edge. Riders piloting machines like the Royal Enfield Himalayan 450 or Scram 411 must avoid slipping the clutch: choose a low gear early, maintain smooth throttle roll-on, and use body positioning and standing on the footpegs to maintain rear-wheel traction over loose rocks. Fuel injection mapping and air filtration also demand rigorous oversight. On fuel-injected bikes, the ECU must adjust injection duration based on signals from the manifold air pressure (MAP) sensor and intake air temperature (IAT) sensor. However, because air density is reduced by almost half, the engine will inevitably produce significantly less power, approximately 30 to 38 percent below rated sea-level output. A 40-horsepower engine effectively performs like a 25-horsepower motorcycle at Yaye Tso. If the air filter is contaminated with the fine silica dust kicked up along the Rong canyon track, airflow is choked further, resulting in sluggish acceleration, black exhaust smoke, and engine surging. Riders must inspect their air filters before leaving Leh and carry a clean replacement filter. On carbureted bikes, ascending to Yaye Tso without re-jetting or leaning the fuel mixture is virtually impossible; the bike will foul its spark plugs and stall on the switchbacks. For four-wheel-drive vehicles like the Maruti Jimny, Mahindra Thar, or Toyota Hilux, low-range transfer case engagement (4L) is mandatory when negotiating the steep moraine switchbacks. Relying on high-range 4WD (4H) overheats transmission fluid and burns automatic transmission clutches on prolonged 18 percent climbs. Engaging low range multiplies torque at crawl speeds, allowing the vehicle to walk smoothly over loose scree and rocky steps without wheel spin. Tire pressures should be lowered to 24-26 PSI on 4x4 SUVs to lengthen the tire contact patch and absorb sharp rock impacts, reducing the risk of sidewall punctures. Operators must carry a 12-volt heavy-duty air compressor, a mechanical bottle jack with a wide wooden base plate, a tire puncture repair kit, and at least 20 liters of extra fuel in secured jerrycans, as four-wheel-drive crawling in low range consumes fuel at more than double the normal highway rate.

Venturing to an altitude of 16,000 feet (4,877 meters) carries grave physiological risks that must never be underestimated. At this altitude, atmospheric oxygen pressure is so low that the human body cannot fully compensate without extensive prior acclimatization. Resting blood oxygen saturation (SpO2) in healthy individuals drops from sea-level norms of 98 percent down to 72-82 percent. Any exertion, such as pushing a stalled motorcycle or walking up a short moraine crest, causes heart rates to spike dramatically, accompanied by immediate breathlessness and lightheadedness. Travelers must never attempt to visit Yaye Tso as their first or second high-altitude excursion in Ladakh. The only safe acclimatization protocol requires having spent at least 4 to 5 days in Ladakh, including successful nights spent at intermediate elevations such as Nubra Valley (10,000 feet) or Chumathang (13,200 feet). Ascending directly from Leh (11,500 feet) to 16,000 feet within a single morning introduces an acute risk of High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE), both of which are life-threatening medical emergencies that require immediate descent. Every vehicle traveling to Yaye Tso must be equipped with a functional fingertip pulse oximeter, medical portable oxygen canisters (minimum two 5-liter cans per person or a pressurized 2.5-liter medical cylinder), and a comprehensive first-aid kit containing Acetazolamide (Diamox), Dexamethasone, and Nifedipine. If any member of your party exhibits signs of persistent severe headache, confusion, ataxia (unsteady, drunken-like gait), or a wet, bubbling cough, turn the vehicle around immediately and descend down to Mahe and Chumathang. In high-altitude medicine, descent is the only definitive treatment. Environmental exposure at Yaye Tso presents additional hazards. Because the lake sits in an open, high-altitude col, it is subject to severe katabatic wind funnels. Wind chill can plunge perceived temperatures below freezing even on bright, sunny afternoons in July. If a motorcycle suffers a puncture or mechanical failure, the rider is instantly exposed to hypothermia. Wearing full multi-layer adventure gear, including windproof outer shells, thermal base layers, winter gloves, and balaclavas, is mandatory. Additionally, the ultraviolet (UV) index at 16,000 feet is extreme; unprotected skin will suffer second-degree solar burns within 20 minutes, and the glare reflecting off the emerald water and surrounding shale can induce solar keratitis (snow blindness). High-protection UV400 sunglasses and SPF 50+ mineral sunscreen are non-negotiable essentials.

Executing a successful expedition to Yaye Tso requires meticulous logistical planning, strict adherence to border permit guidelines, and autonomous fuel management. Because this region borders sensitive strategic sectors monitored by the Indian Army and the Indo-Tibetan Border Police, security protocols are strictly enforced. Permit Requirements: - Indian Domestic Travelers: Must obtain an official Inner Line Permit (ILP) issued by the Deputy Commissioner (DC) Office in Leh. Crucially, the permit must explicitly list 'Mahe', 'Chushul', and 'Kaksang La'. Standard permits that only endorse 'Tso Moriri' or 'Pangong' may be rejected by ITBP personnel at Mahe Bridge if you attempt to turn northward into the Rong valley. Always carry at least 4 to 5 physical printouts of your approved permit, along with government-issued photo IDs (Aadhaar Card, Passport, or Driving License). - Foreign Nationals: Under current Ministry of Home Affairs (MHA) regulations, foreign tourists are permitted to travel along the primary Leh-Chumathang-Mahe-Tso Moriri highway under a Protected Area Permit (PAP). However, foreign access beyond Rong toward Kaksang La and Chushul is strictly regulated and frequently restricted due to proximity to the Line of Actual Control (LAC). Foreign travelers must verify current security clearances with an authorized travel agent in Leh before planning an itinerary through this col. Fuel and Range Calculations: The total round-trip distance from Leh to Yaye Tso and back via Mahe is roughly 370 kilometers. If you plan to continue across Kaksang La to Chushul, Spangmik (Pangong Tso), and return via Chang La, the total circuit exceeds 460 kilometers through brutal terrain where fuel consumption increases by 35 to 50 percent due to low-gear crawling, loose gravel, and high-altitude power loss. The last official retail fuel pump on this route is located at Karu (45 km from Leh). There are zero authorized petrol stations in Chumathang, Mahe, Rong, or Kaksang La. - Motorcycles: Bikes with standard 12-to-15-liter fuel tanks must carry a minimum of 5 to 10 liters of auxiliary fuel in approved fuel canisters or bladders. - 4x4 Overland SUVs: Must carry at least 20 liters of supplementary fuel in metal jerrycans. Never rely on black-market fuel sold in unsealed plastic bottles at village stalls, as it is frequently contaminated with kerosene or water, which can destroy high-pressure fuel pumps and injectors at high altitude. Communication and Navigation: Beyond Chumathang, commercial cellular mobile connectivity (including postpaid BSNL, Jio, and Airtel) drops completely. In the Rong canyon and around Yaye Tso, there is absolute zero network coverage. Satellite phones are heavily restricted in India; travelers should carry an offline GPS navigation system (such as Garmin handheld units or downloaded offline maps on Gaia GPS / OsmAnd). Always inform your rental provider (Ride & Fire) in Leh of your precise planned route and estimated time of return before departing into the Kaksang wilderness.

Climbing the unpaved moraine trail from Rong village to Yaye Tso and the high pass of Kaksang La is one of the most mechanically demanding off-road tasks in the Himalayas. The combination of an 18 percent incline, loose marble-sized shale gravel, sharp rock steps, and an altitude exceeding 15,000 feet creates extreme transmission and clutch strain on motorcycles and vehicles alike. On adventure motorcycles like the Royal Enfield Himalayan 450, Scram 411, or Hero XPulse 200, the primary mechanical risk is catastrophic clutch plate overheating. When ascending loose, steep switchbacks, riders who lack off-road confidence often make the critical error of slipping the clutch continuously in second gear to prevent the engine from stalling. In the thin atmosphere of 16,000 feet, where the engine is already robbed of 35 percent of its torque, sustained clutch slippage generates intense frictional heat within the clutch pack. Temperatures inside the clutch basket can exceed 250 degrees Celsius within three to four minutes. At these temperatures, engine oil breaks down thermally, cork-based friction plates glaze and char, steel drive plates warp from heat stress, and the clutch cable loses its tension, leading to total loss of forward drive. To conquer these severe moraine inclines without damaging your machinery, riders must practice disciplined off-road clutch techniques: 1. Select First Gear Early: Never attempt to carry second gear through loose shale switchbacks above Rong. Downshift into first gear well before the turn, keeping the engine RPM in the middle of its powerband where the water pump and oil pump circulate fluids at maximum volume. 2. Feather, Do Not Slip: Use the clutch lever only for momentary modulation to control wheel spin or pop over rock steps. Once rolling, release the clutch lever fully to achieve complete mechanical lockup between the friction plates and steel plates, transferring 100 percent of engine torque directly to the rear tire. 3. Stand on the Footpegs: Standing on the motorcycle footpegs lowers the center of gravity, centers rider mass directly over the swingarm pivot, and allows the rear tire to dig into the loose shale for maximum traction. Look ahead through the turn rather than down at your front wheel. 4. Emergency Stalling Recovery: If you stall on an 18 percent loose incline, never pull in the clutch and try to roll backward. Immediately apply both brakes, plant your uphill foot firmly on the slope, leave the motorcycle in first gear as an engine brake, and dismount safely. Catch your breath, clear large rocks from your rear tire path, and use the clutch friction zone smoothly while walking the bike forward to regain momentum.

Because Yaye Tso and the high pass of Kaksang La represent one of the most remote and isolated mountain corridors in the entire Union Territory of Ladakh, travelers must operate under the assumption that zero outside emergency assistance will be available in the event of a crisis. From the moment you turn off the paved Indus highway at Mahe Bridge, all commercial mobile cellular towers disappear. Between Rong village and Chushul, there are no medical dispensaries, no police outposts, no vehicle repair workshops, and no passing civilian traffic. In this extreme environment, self-reliance is not merely a slogan but a non-negotiable prerequisite for survival: 1. Convoy Travel Requirement: Single-vehicle solo expeditions into the Yaye Tso and Kaksang Range are strongly discouraged. Always travel in a minimum convoy of two adventure motorcycles or at least one 4x4 support vehicle. If one motorcycle suffers a bent wheel rim, a cracked crankcase from a boulder strike, or an electrical burnout, the second machine can ferry tools, provide tow assistance, or carry the stranded rider back down to the medical facility at Chumathang. 2. Emergency Satellite Messaging: While traditional satellite phones (such as Iridium or Thuraya handsets) are strictly regulated and prohibited for civilian tourists under Indian telecommunications and border security laws without specialized government defense clearances, travelers should utilize offline GPS navigation devices and pre-arranged check-in intervals. Establish a strict check-in protocol with your fleet rental manager at Ride & Fire in Leh: agree upon an exact deadline hour by which your convoy must reach Chushul or return to Mahe. If you fail to check in within six hours of the agreed milestone, the rental operations team can initiate emergency notification to the Leh District Disaster Management Authority (DDMA) and ITBP regional headquarters. 3. High-Altitude Field Trauma Medical Kit: In addition to standard blister bandages and antiseptics, your medical kit must contain dedicated high-altitude pharmaceuticals: Diamox (Acetazolamide 250mg) for acute altitude sickness prophylaxis, Dexamethasone 4mg tablets for High Altitude Cerebral Edema (HACE), Nifedipine 20mg for High Altitude Pulmonary Edema (HAPE), and heavy-duty analgesics for traumatic injuries. Carry rigid aluminum finger and limb splints, self-adhesive cohesive bandages for sprained ankles, and a minimum of three space blankets (mylar hypothermia sheets) to prevent lethal body heat loss in an immobilized patient while awaiting transport.

Planning an expedition to Yaye Tso requires an intimate understanding of the extreme seasonal meteorological rhythms that govern the Kaksang Range and eastern Ladakh. Because the lake sits at 16,000 feet, winter conditions dominate for more than seven months of the year, transforming the landscape into a frozen, sub-zero fortress. Winter and Early Spring (November to Late May): From early November onwards, daytime temperatures plummet below minus 15 degrees Celsius, while nighttime readings routinely reach minus 30 to minus 38 degrees Celsius. The surface of Yaye Tso freezes solid into a dense sheet of turquoise and white ice up to two meters thick. Massive snowdrifts accumulate across the high passes of Kaksang La and the Rong gorge, creating avalanche chutes and blocking all vehicle access. The small village of Rong enters winter isolation, relying on stockpiled dried foods and yak dung fuel. Attempting to reach Yaye Tso during this window is strictly impossible for motor vehicles. Late Spring and Thaw (June): As summer arrives in early June, the Border Roads Organisation (Project Himank) deploys heavy bulldozers and snow cutters to clear the high pass of Kaksang La. During this transition period, intense solar radiation triggers rapid snowmelt. The trail above Rong experiences significant mud slush, falling rock hazards, and surging stream crossings where glacial meltwater tears across unpaved switchbacks. While the lake begins to thaw, displaying stunning floating turquoise ice floes, the track is rough and requires experienced off-road riding skills. Peak Expedition Window (July to August): July and August represent the prime weather window for exploring Yaye Tso. Daytime temperatures at 16,000 feet hover between a pleasant 10 and 18 degrees Celsius under brilliant sunshine, although nighttime frosts remain common. The emerald coloration of the lake reaches its maximum optical radiance as high-altitude ultraviolet rays interact with suspended volcanic minerals. Glacial melt streams are predictable, and the trail over Kaksang La to Chushul is generally open, allowing complete traversals. Autumn Transition (September to October): September is favored by seasoned motorcycle riders for its crystal-clear skies, minimal rainfall, and crisp autumn air. Daytime temperatures range from 5 to 14 degrees Celsius, but nights become bitterly cold (minus 5 to minus 15 degrees Celsius). By mid-October, the first severe winter blizzards arrive, laying fresh snow across Kaksang La and triggering rapid ice formation along the lakeshore, effectively closing the corridor for the season.