Glacier Hiking in Alaska: What Moving Ice Actually Looks Like
There’s a moment that happens on every Root Glacier hike. You’re standing on centuries-old ice, and someone asks: “Wait, is this thing actually moving right now?”
The answer? Yes. Absolutely yes.
What looks like a solid, frozen landscape beneath your crampons is actually flowing downhill like an incredibly slow river. During active periods, some sections move more than three feet per day. Stand still long enough (not recommended), and the glacier would literally carry you downvalley. Understanding this movement changes glacier hiking from sightseeing into something more specific. You’re watching geological processes that most people never get to witness firsthand.
After 14 years guiding glacier hikes in Wrangell-St. Elias National Park, we’ve learned to read ice the way river guides read whitewater. Every crevasse, every crack, every blue streak tells a story about forces operating on timescales that span decades to millennia. Once you start seeing these stories, you can’t unsee them.
How Glaciers Actually Move (The Science Behind the Ice)
Glacial ice is weird. It’s solid, but it flows. It’s frozen, but it moves.
Here’s what’s happening. Under the immense pressure created by hundreds of feet of accumulated ice, glaciers flow plastically. They deform and move in response to gravity while maintaining their solid appearance. Glaciologists call this plastic deformation. It’s what allows glaciers to conform to valley shapes while simultaneously carving new channels through the landscape.
A glacier forms when snow accumulates over time, turns to ice, and begins to flow outwards and downwards under the pressure of its own weight. Think of it like super slow-motion honey. Apply enough pressure over enough time, and even solid ice will flow around obstacles, squeeze through narrow valleys, and reshape itself to fit available space. Except instead of minutes, we’re talking about processes that unfold over years and decades. nsidc
If the accumulated snow survives one melt season, it forms a denser, more compressed layer called firn. The snow and firn are further compressed by overlying snowfall, and the buried layers slowly grow together to form a thickened mass of ice. nsidc
This creates a conveyor belt. Ice formed at high elevations slowly flows downhill toward the terminus, where it melts into rivers or calves into lakes. The snow falling on the glacier today won’t reach the terminus for decades. Maybe centuries, depending on the glacier’s size and movement rate.
Temperature plays a bigger role than most people expect. The glaciers here in the Wrangells operate under what scientists call temperate conditions; ice temperatures hovering near the melting point. This creates conditions favorable for plastic flow, which explains why Alaska glaciers remain so active and dynamic compared to polar glaciers that move much more slowly in colder temperatures.
What to Look For on a Glacier Hike in Alaska
Once you know what to look for, glacial movement is visible everywhere.
Crevasses
Crevasses are cracks in glacier ice. At locations where a glacier flows rapidly, friction creates these giant cracks. They may form on the glacier surface, on its underbelly, or on the sides. Every crevasse tells a story about the terrain underneath and the forces acting on the ice above. nsidc
During our Root Glacier hikes, we point these out constantly. Not just for safety, but because they’re fascinating. That massive crack you’re carefully navigating around? It formed because the glacier’s moving faster on one side than the other, or because the ice is stretching as it flows over a bump in the bedrock below. The patterns aren’t random. They’re readable if you know what you’re looking at.
Moraines
As ice flows downhill, it transports rock debris from high elevations down to the terminus, where it accumulates in characteristic patterns. Medial moraines — those dark rocky lines running down the center of many glaciers — form where two tributary glaciers merge. Each line shows exactly where ice from different source areas flows together while maintaining distinct boundaries for miles.
Icefalls and Seracs
Icefalls often occur when glaciers flow over a steep drop. That portion of glacier ice flows faster and becomes heavily crevassed. Those dramatic formations visible from many of our hiking routes represent the glacier’s response to underlying bedrock creating acceleration zones and compression areas. Instead of flowing smoothly, the ice fractures into towering blocks and spires. nsidc
Every wrinkle, crack, and formation on a glacier’s surface represents the ice adjusting to the terrain beneath it. Nothing up there is random.
Why Alaska Glacier Hikes Feel Different Every Season
Glacial movement isn’t constant. It varies throughout the year in response to temperature changes, precipitation patterns, and meltwater production.
Summer acceleration happens when surface melting creates meltwater that works its way to the glacier bed, lubricating the interface between ice and bedrock. A glacier may slide on a thin layer of water at its base, from glacial melting due to the pressure of the overlying ice, or from water that has worked its way through cracks in the glacier. During peak summer melt, movement rates can increase several times over normal winter speeds. The ice literally moves faster in July than it does in May. nsidc
Glaciers may surge, racing forward several meters per day for weeks or even months. In 1986, the Hubbard Glacier in Alaska surged at the rate of 10 meters (32 feet) per day across the mouth of Russell Fjord, damming water in the fjord and creating a lake within two months. When a glacier surges, routes that worked last year might be impassable this year. Ice features that made for good photos might have moved or disappeared entirely. It’s one reason return visitors often find completely different conditions. They’re literally looking at a different glacier than they saw before. nsidc
Movement rates also peak during warm afternoon hours as surface melting produces maximum meltwater. These daily fluctuations create the sounds many visitors notice — creaking, groaning, occasional sharp cracking as ice adjusts to changing stress patterns throughout each 24-hour period.
When you hear those sounds on a glacier hike, you’re not just hearing ice. You’re hearing movement in real time.
Alaska’s Glaciers Are Changing Fast: What That Means for Hikers
Alaska has warmed twice as fast as the rest of the United States during the last several decades. Alaska’s glaciers are in steep decline and are among the fastest melting glaciers on Earth. One impact of climate change on maritime glaciers is an increase in the altitude of the rain-snow line. As this line rises, rain falls more frequently in high-elevation settings, decreasing the amount of snow accumulating on glaciers and negatively influencing annual mass balance. alaskaalaska
The numbers from global monitoring back this up. The American Meteorological Society reported that alpine glaciers around the world continued to lose mass for the 34th consecutive year, with average annual mass loss accelerating from 214 millimeters (8.4 inches) per decade in the 1980s to 896 millimeters (35.3 inches) per decade in the 2010s. nsidc
Here’s the counterintuitive part. Retreating glaciers often show acceleration in movement rates as internal stresses adjust to changing ice thickness and terminus positions. Shrinking glaciers sometimes move faster than stable ones, creating more dynamic ice features that make glacier viewing more dramatic even as overall ice volumes decline.
It’s a hard thing to sit with. The glaciers are more active and more photogenic than ever. They’re also disappearing faster than at any recorded point in history.
Abrupt changes in the occurrence of glacial lake outburst floods are typical in a rapidly changing climate. Routes that remained stable for decades may become impassable as crevasse patterns shift. New terrain becomes accessible as retreating ice exposes previously hidden ground. Our guides continuously adapt routes and safety protocols to keep up with these changes. alaska
We’ve watched these glaciers change over 14 years of guiding in Wrangell-St. Elias in ways that would have seemed unimaginable to an earlier generation. It makes the work more challenging. It also makes the experiences more urgent. These glaciers won’t look like this forever.
Walking on Deep Time: What the Ice Actually Contains
Glacial ice can be as old as several hundreds of thousands of years, making it valuable for climate research. The ice beneath your feet during a Root Glacier hike fell as snow when your great-grandparents were children. Maybe earlier. That snow worked its way down from the high country over decades, compressed and changed along the way, until it ended up right where you’re standing. nsidc
Scientists drill and extract ice cores from glaciers and ice sheets to analyze trapped air bubbles, which reveal past atmospheric composition, temperature variations, and types of vegetation. You can observe the same historical record in the walls of crevasses. Those faint horizontal lines in the blue ice? Annual layers of snowfall, preserved like tree rings. Each layer represents a winter’s worth of precipitation, gradually compressed until the air was squeezed out and only dense blue ice remains. nsidc
The glacier movement also created the landscape we hike across, raft through, and camp beside. The U-shaped valleys, the hanging valleys visible from our campsites, the peaks surrounding every route — all products of glacial movement operating over millions of years. Current glacier movement continues this landscape modification. Every trip occurs in terrain that’s still being shaped.
How Experienced Glacier Hike Guides Read the Ice
Experienced glacier travelers develop skills in reading ice conditions that reveal current movement patterns and predict changes affecting safety and route selection.
Fresh crevasses appear as clean breaks with sharp edges. Older cracks show weathered edges and may be partially filled with snow or debris. Understanding these differences helps predict ice stability and plan safe routes across dynamic surfaces.
Our guides read these features constantly. That snow bridge you just crossed? They evaluated it based on temperature, recent weather, time of day, angle of the sun, depth of the crevasse beneath, and a dozen other factors you probably didn’t notice. On moving ice, what looks stable might not be. What looks sketchy might actually be fine.
Surface features like pressure ridges, compression zones, and flow lines all tell stories about current movement patterns and the underlying terrain influencing ice flow. Learning to read these features builds real understanding of the forces creating the ice formations you’re walking through.
Constant movement means glacier hiking routes require continuous monitoring by guides who understand both current conditions and likely changes. This is why we live here, monitor conditions year-round, and why our guides know these glaciers the way other people know their neighborhoods. On ice that’s always changing, local knowledge isn’t just helpful. It’s essential.
Book a Private Glacier Hike in Alaska’s Wrangell-St. Elias National Park
When you understand that glaciers move, everything changes. That blue ice you’re standing on is flowing. Those crevasses you’re navigating are growing, shifting, changing position. That serac field you’re photographing will look different next month.
Glacier hiking in Alaska isn’t just a cool activity. You’re watching geological processes in action, reading landscape history in frozen form, standing on ice that connects to centuries of weather patterns and climate records.
And you’re doing it in one of the few places left where glaciers remain accessible enough to explore safely, yet wild enough to feel genuinely remote. Where guides with years of local knowledge can show you not just what glaciers look like, but how they work, why they matter, and what their changes mean going forward.
That’s the kind of glacier hiking we do. Not just crampons and photos (though there are plenty of both). Genuine engagement with dynamic ice in a landscape that’s always changing.
Ready to walk on history? Book a private Root Glacier hike
McCarthy River Tours holds an NPS special use permit for Wrangell-St. Elias National Park. Our guides hold Swiftwater Rescue and Wilderness First Responder certifications (80-hour minimum) and monitor glacier conditions year-round to keep routes current and safe. Questions? Call 888-609-RAFT or email reservations@raftthewrangells.com.