One river, 18,000 feet, 1,500 miles. In the fall of 2013, photographer and videographer Pete McBride, along with professional climbers Jake Norton and Dave Morton, followed the Ganges River from snow to sea. All this week, Proof takes you on their 45-day journey—by foot, boat, bike, aircraft, rickshaw, bus, train, and even elephant—as they track every mile of this sacred river.

September 17-28, 2013

Just before sunset, the snow starts to fall. The flakes are wet and heavy. Jake looks up and says as much to the sky as to us, his climbing partners, “This feels like one of those monsoon storms that stick around.”

Dave and I listen to Jake’s words, but there is nothing to do except button up. We are high in the Garhwal region of the Indian Himalaya, standing at 17,500 feet atop the giant Gangotri glacier, surrounded by 23,000-foot peaks, many unclimbed. It is said to be the birthplace of India’s sacred river, the Ganges. It has taken us nearly ten days to get here—six of them by foot walking through treacherous, glacial moraine. We are miles from any whisper of civilization. But due to our proximity to India’s northwestern border with Pakistan, Indian law prohibits satellite phones. International tensions with Pakistan are hotter than normal, boiling even. We are highly aware that any rescue requiring support (helicopters), is out of the question.

We came to this remoteness to claw our way up the unclimbed Chaukhamba IV, a 22,487-foot, glacial-clad granite monster standing like a sentinel protecting the Gangotri glacier at its feet. Avalanche conditions are ripe, so we have targeted another 22,200-foot peak just west. It too has never been climbed, or even named. We are poised to move upward tomorrow. Ropes, helmets, crampons, and ice axes sit ready, waiting outside our tents.

A stubborn monsoon season might say otherwise though. As darkness seeps over us, the wet, heavy flakes change. The soft sound of falling snow has morphed to a frozen, small hail. Miniature tap dancers performing on our nylon roof, I think. We lie in our sleeping bags cracking jokes about our situation. Who packed skis? All of us are intently focused on the sound of the storm. I try to keep worry to a slow percolate.

The steady creaks and moans of the glacier that kept me awake previous nights have subsided. And the steady roar of water pouring down the glacier has also gone mute. Just the icy snow dance on our tent. I wonder if the haunting loon-like call of the male Himalayan snowcock will wake us in the morning like it has before.

Sometime around midnight a new sound jolts Jake and me upright in our bags. A low rumble … no, distant thunder … no, echoing giant thunder. Avalanche. At first we hear it from afar—high up on Chaukhamba, I presume. But steadily the rumble grows louder, stereo even. Jake and I look at each other. “How far are we from the mountain?” I ask, starting to eye my boots. Jake assures me we are fine. Ten minutes later another roar, even louder. Jake eyes his boots.

For the next five hours, the avalanches continue. Their sounds vary between that of distant thunderstorms and the crack of artillery fire—building-size blocks tumbling from above. Some avalanches rumble over a minute. Throughout the night, I count 36.

At 5:30 a.m., we come to the conclusion that our climbing mission is over. If we don’t move, the monsoon won’t let us. It is time to pack up and fight/flee our way down. As I mine for buried tent stakes, I measure over three feet of snow. It is still snowing, hard. The soupy light is so flat, I get disoriented when I stand. The call of the snowcock is absent. Everything is absent except snow.

Having grown up in the Rocky Mountains and spent the majority of my life in snowy environs, I’m dumbfounded. I’ve never seen such a surge of frozen moisture before, ever.

Over the next six hours we posthole through thigh-deep, concrete-like snow, straining under oversize loads. Our climbing ropes remain behind—too heavy for a single load. We mark their location with GPS coordinates, optimistically hoping someone can find them later. In ten hours, we make just three miles to Advance Base Camp. Our third tent is completely buried, hidden. Dave, who has guided all seven summits and stood atop Everest six times, says it is the “most worked he has been in a long time.” I can barely smile at the comment. I’m shattered.

We reach Base Camp the following night. I’m so tired I can barely eat. And two days later we reach the rustic ashram of Silent Baba, a sadhu who hasn’t spoken in seven years—his form of reverence to Ma Ganga. His tiny structure sits at 14,200 feet, in the shadow of the Bhagirathi, Meru, and Shivling, some of the most stunning peaks I’ve witnessed. Wild ibex linger in the meadows beyond his stone sanctuary. Baba serves us homemade chai and we sit in silence, watching the mountains, grateful we aren’t stranded.

Slightly defeated by our abandoned climb, we push downstream past Gaumukh, “the cow’s mouth,” where the Ganges pours out beneath the collapsing foot of the Gangotri Glacier. This transition of ice to river is spiritually powerful and many Hindu pilgrimage here. The exact location, however, is moving upstream at roughly 60 feet a year—the hand of climate change at work.

Then, suddenly, after weeks on foot, we return to the wheeled travel of 4x4s and move downstream through the scoured canyons of a gravity-fueled river. The roads that were washed out when we came in are now repaired, barely. “It feels like we are driving on a sandcastle,” says Dave.

When we enter the lower foothills, the power of the Ganges visibly stops. Stretched before us is the Tehri Dam and reservoir, one of the largest and most controversial hydroelectric projects in the world. To quench a growing thirst for electricity, the Tehri project submerged 40 villages and physically stopped Lord Shiva’s flow.

The sacred headwaters are clearly behind us. Time to start looking downstream.

Next: Do you know where your shoes come from? Industry on the Banks: Deep Inside Kanpur’s Tanneries

The Ganges River expedition was made possible with funding from Microsoft, Eddie Bauer, National Geographic Society’s Expeditions Council, Ambuja Cement India, and Hach Hyrdolab. The full expedition team includes photographer and videographer Pete McBride, videographers and professional climbers Jake Norton and Dave Morton, and second camera Ashley Mosher.