The Harding Icefield caps the Kenai Mountains with about 700 square miles of ice — the largest icefield entirely within the United States — and at least 38 glaciers flow outward from it. Roughly 51% of the park is under ice, across a park of about 669,984 acres. Those glaciers carved the deep valleys that became the fjords, but only three of the park's fjords still hold active tidewater glaciers today. Figures vary by source, so treat them as approximate.
The Harding Icefield is the engine behind almost everything a visitor comes to see. It is fed by enormous snowfall, and from its high plateau of ice, glaciers spill outward in every direction — some ending in valleys, some in lagoons, and a few still reaching all the way to the sea. Understanding the icefield first makes the coastline, the calving glaciers and the sea stacks along a cruise route fall into place.
Ice carved the valleys, then the sea flooded them
As the glaciers of the Harding Icefield flowed toward the coast, they ground out deep U-shaped valleys in the Kenai Mountains. Over time the land subsided and sea levels rose, and the ocean flooded those carved valleys. The result is the fjords: long, steep-walled arms of the sea reaching back toward the ice.
The islands and sea stacks visitors pass on a cruise are the tops of what were once mountains — former summits left standing above the flooded valley floors. The same process explains why so few glaciers still touch salt water: as the ice has pulled back, most have retreated into their valleys, and only three of the park's fjords still hold active tidewater glaciers today.
The kinds of glaciers you'll see
Glaciers here take different forms depending on where they end.
Tidewater
Aialik · Holgate · Northwestern
- Terminate in the sea and calve icebergs off their face
- Only three fjords still hold active tidewater glaciers
- The reason full-day fjord cruises exist
Valley & piedmont
Bear Glacier — the park's largest
- Flow down and spread out, ending on land or in a lagoon
- Bear Glacier ends in a growing, iceberg-filled proglacial lagoon
- Building-size bergs drift in the lagoon
Hanging & cirque
Higher on the mountains
- Smaller glaciers set high in bowls and side valleys
- Hang above the main valleys carved by larger glaciers
- Seen on the slopes above the icefield and fjords
Which glacier is which, and how to see it
The glaciers most visitors ask about, and the way each is reached.
| Glacier | Type | How to see it |
|---|---|---|
| Exit Glacier | Valley (off the icefield) | The only road-accessible glacier — walk to it and start the Harding Icefield Trail. See Exit Glacier. |
| Aialik & Holgate | Active tidewater | In Aialik Bay; reached on full-day cruises from Seward. |
| Northwestern Fjord | Three active tidewater glaciers | The deepest cruise destination in the park, reached on the longest full-day tours. |
| Bear Glacier | Valley/piedmont (the park's largest) | Ends in an iceberg-filled lagoon; reached by kayak or helicopter rather than standard cruises. |
Enormous snowfall, ice in a few years
The Harding Icefield exists because far more snow falls each winter than melts each summer. The icefield receives very heavy snowfall — commonly cited at around 400 or more inches per year — while the lower Exit Glacier area alone averages close to 200 inches of snow annually. That surplus feeds the ice that flows outward as glaciers.
With snowfall that heavy, glacial ice can form remarkably fast. In Alaska, ice can develop in just a few years through firnification, the process by which fresh snow compacts, recrystallizes and eventually turns to solid glacier ice under the weight of the snow above it.
In one line: the icefield is about 700 square miles of ice, feeds at least 38 glaciers, and covers roughly 51% of a park of about 669,984 acres. Figures vary by source — treat them as approximate.
A changing icefield. Most of the park's glaciers are retreating, and Exit Glacier's retreat is marked year by year along its trail. For the sourced figures on how much and how fast, see Glacier Retreat.
Glacier & geology questions
The Harding Icefield covers about 700 square miles of ice atop the Kenai Mountains, making it the largest icefield entirely within the United States. It is fed by enormous snowfall, commonly cited at around 400 or more inches per year. Figures vary by source.
At least 38 glaciers flow outward from the Harding Icefield. Roughly 51% of the park is covered by ice, and the park itself is about 669,984 acres. Only three of the park's fjords still hold active tidewater glaciers today.
A tidewater glacier flows all the way down to the sea and terminates in salt water, where it calves icebergs off its face. Aialik, Holgate and the Northwestern Fjord glaciers are the active tidewater glaciers visitors reach on cruises.
Bear Glacier is the park's largest. It is a valley and piedmont glacier that now ends in a growing, iceberg-filled proglacial lagoon holding building-size icebergs, and it is typically reached by kayak or helicopter rather than on standard boat cruises.
Exit Glacier is the only road-accessible glacier and can be walked to. Aialik and Holgate are active tidewater glaciers in Aialik Bay reached on full-day cruises, and Northwestern Fjord, the deepest cruise destination, holds three tidewater glaciers. Bear Glacier's lagoon is reached by kayak or helicopter.
Related guides
Kenai Fjords tours & experiences
Other experiences you might enjoy — glacier and wildlife cruises, sea kayaking and flightseeing from Seward and Aialik Bay.
See the ice for yourself
The tidewater glaciers are reached only by water. Compare cruises from Seward and pick the run that reaches the glaciers you want to see.