Even in a state as saturated with dramatic peaks and geological marvels as Colorado, it’s thrilling to get up close and personal with something as grand — and as emblematic of our ballooning climate change crisis — as a glacier.

Given the near certainty of continued climate chaos in coming years, seeing these remnants of the last ice age is becoming a catch-them-while-you-can prospect. To wit, according to the World Glacier Monitoring Service, the Earth’s rate of glacial loss has increased by more than 400% since the 1980s; 2023 was the 36th consecutive year that the world’s glaciers (those being tracked) have shrunk.

So, if you’ve worn out the trail to the Front Range’s iconic St. Mary’s Glacier (now recategorized as a “semi-permanent snowfield”), consider a different kind of journey — one that requires a passport and a healthy sense of adventure — to get your glacier fill: a rafting expedition down the remote glacier-fed Tatshenshini River that flows from the rapid-filled canyons of the Yukon in northwestern Canada through the braided channels of British Columbia and, after it joins the rugged Alsek River, toward the dramatic peaks of Alaska’s Fairweather Range.

Some say this 160-mile trip down one of North America’s last truly wild river systems rivals the Grand Canyon in terms of scenic wonder. Guided by Canadian River Expeditions (CRE) out of Whitehorse in the Yukon, it spans 11 days of paddling, floating, camping, exploring and hiking through the wilds of one of the world’s most expansive internationally protected areas, which is also home to the Earth’s largest non-polar ice cap and a vast population of grizzlies, moose, caribou, wolves and bald eagles.

Three rafts, each carrying up to four passengers and one experienced guide, caravan through the riverscapes of Tatshenshini-Alsek Provincial Park and Glacier Bay National Park and Preserve to where the river empties into the Gulf of Alaska. The inflatable rafts are meticulously rigged with camping gear, personal packs, provisions for three hearty, from-scratch meals a day, a full kitchen and outdoor toilet setup, and safety equipment to sustain 14 or so individuals over the duration. There is no resupplying in what CRE calls the “land with no roads.”

The end game: Glaciers. Many of them. But it’s not until a week into the trip that you’ll be treated to the majestic sight. At a camp called Melt Creek near the confluence of the Tatshensini and Alsek rivers, up to 27 glaciers might peak through the mist at any given time. All of which is to say, the trip is a bit of a work-for-your-reward experience. And, it is work, at times: Unloading and reloading the aforementioned haul every one or two days for 10 nights of riverfront camping carries some physical implications. And, although you need not be experienced, rafters are encouraged to paddle (sometimes in challenging weather) while the highly skilled guides helm the oars.

The trip launches at the inland narrows of “the Tat” after a half-day drive up the Alaska Highway from Whitehorse, including a stop to visit with First Nations elders — an intimate reminder to respect and appreciate the traditional homelands of the Champagne and Aishihik First Nations.

Over the next few days, gentle ripples become Class III rapids that tumble through gorges (dry suits and helmets provided), and ever-widening channels carry the raft train to gravelly beaches and wildflower-strewn meadows that become tent sites tucked in the shadow of breezy ridgelines. Ice-cold (literally) glacial creeks near camp beg for a refreshing dip to ease the insistence of a sun that doesn’t set until 10:30 p.m. Bald eagles soar overhead while fleeting glimpses of grizzlies onshore (and plenty of fresh tracks near camp) keep the crew alert.

In calm-water stretches and over dinners of freshly grilled arctic char or sizzling steaks (meals so good they warrant a recipe book), the guides share their impressive wealth of trivia about this backcountry. For example, how conservation groups shut down a lucrative copper mining proposal in the 1980s to save the river system and surrounding untouched wilderness from the devastating effects of roads, trucking, pipelines and acid mine drainage, paving the way for international park and UNESCO World Heritage Site designations.

Such legislative protections are critical, but they can’t halt climate change. That much is clear at Walker Glacier, named such because rafters could once pull right up to the glacier’s terminus at river’s edge and hop off the boat to walk the ice. In the past few decades, it has receded more than a mile, leaving in its wake an obstacle-laden lake that cuts off most access. From camp, however, an easy meander around the lake’s outskirts still allows for killer views. Don’t forget a beverage, and leave room for ice; mini icebergs that have calved off the glacier often drift close enough to chisel off a cube or two for a glacial cocktail worthy of a toast.

Celebration, though, can easily give way to contemplation out here. “There aren’t a lot of places where we’re actively watching glaciers recede around us,” says CRE guide Carson Yach. “And to have that happen on the time scale we’re seeing, on a day-to-day, week-to-week, year-to-year basis … for the millions of people that live on shoreline communities and low-lying areas, if all these glaciers just melt and disappear, where are those people going to go? Where is our water going to continue to come from? People don’t see these glaciers. They don’t understand. How do you get people to care about things they’ve never experienced?”

Walker is a precursor to the culmination of the trip at Alsek Lake, an almost otherworldly pool of turquoise waters strewn with mystical-looking ’bergs that have sloughed off Alsek and Grand Plateau glaciers, yawning for miles around the perimeter of the lake. As you’re hammering in your tent stakes for the final two nights in Glacier Bay National Park and Preserve, you’ll likely hear a deep, rolling rumble, rising ominously from somewhere beyond the pine-fringed clearing of the small island camp. It almost sounds like thunder. When the low roar swells again, you’ll realize the eerie reverberations are coming off the lake, where ripples are churning outward from a formidable angular iceberg the color of aquamarine.

It’s one of many sculptural ice masses floating in Alsek Lake like luminous castles. The disconcerting roar? That’s the noise that happens when a block rips off the iceberg and rolls into the water — or when a giant ice slab calves off one of the surrounding glaciers into the lake, thus becoming the iceberg itself. Periodically over the next 48 hours, the rumbling descends on the group like a bell ringing every time a glacier loses its ice.

The sound might haunt you long after you’ve paddled the last couple of hours to the takeout beach near a fishing village called Dry Bay, pulled ashore, derigged and deflated the rafts, and loaded onto an ATV shuttle for the quick ride to a barely-there airstrip. A tiny plane flies the team and gear back to Whitehorse — a spectacular aerial rewind over the past 11 days.

“Every time I come down, it’s different,” says CRE guide and trip leader Natalie Sands, who’s been navigating this river system for 15 years. “Every time I see all those changes, it’s almost like an urgency I feel to make sure I keep coming every year to be able to capture it — because it’s alarming how quickly it’s changing.”

It’s a sentiment that plays into an idea known as “last chance tourism,” a phenomenon that might conjure up the image of, say, a cruise ship. But with CRE — a company with a history of environmental stewardship in the region — witnessing this real-time dissolution of our planet’s most fragile resources hits differently, more viscerally, because you work for it — work in harmony with the river for it, instead of standing on a cruise deck and hopping in a kayak for a couple of hours.

There’s something so sublime about floating alongside the parts of a glacier that are drifting away out to sea, like the discarded pieces of our past not strong enough to survive the Earth’s future. The vantage point is unlike any hiking or cruising excursion you can dream up — one that highlights the magnitude of our smallness — and arguably the best way to marvel at one of the Earth’s most resplendent natural phenomena before there’s not enough glacial mass left worth marveling at.