Glaciers and glacier travel: Background for hikers

Rivers of Ice

Glaciers can be an obstacle for hikers and mountaineers -- or they may be the objective.

A river of ice: This sense of a glacier is often more clear from a distance.

   What is a Glacier?   

Quite briefly, it's a permanent, moving body of ice. Or, as it's often phrased, a river of ice.

Glaciers are formed when snow falls in an environment so cold that not all the snow has time to melt during the summer. Over a period of years, the weight of new snow forces out the air trapped by previous layers. Fallen snow compresses into ice. Meltwater from the top trickles down, and refreezes, 

On a mountainside, or any area that's not flat, the weight of this ice eventually causes it to slowly flow, or creep, downhill. As it moves lower, more snow accumulates at the top, compressing into ice. Meanwhile, the ice at the bottom of the glacier reaches a lower and warmer altitude, and melts.

New Zealand's Fox Glacier, like many in temperate climates, challenges hikers with giant blocks of ice. Nonetheless, much of it can be negotiated simply with crampons, a hiking stick, and an experienced guide, without a need for ropes.

More about glacier hiking

   Glacier Flow   

The movement of a glacier, of course, is far slower than that of a river. In some ways, these flows are analogous, but there are notable differences.

Some of the glacier creep takes advantage of the natural elasticity of the ice, but often, cracks and crevasses form as the glacier continues its downward flow.

Kayakers know that when water goes around a bend in a river, water on the outside goes faster. Likewise, as glacial ice flows down a twisting valley, ice on the outside speeds up, creating crevasses. Likewise, a steeper glacier will usually have more crevasses than one on a gentler slope. Most crevasses go no more than about 100 feet; below that point, the extreme pressure on the ice keeps it pushed together. 

Glaciers can be as small as a city block; or several hundred (or more) miles in length. Although a glacier appears from a distance to be simply a giant mass of ice, the interior can be riddled with underground tunnels, rivers, and even lakes. Meltwater from the surfaces is carried through the tunnels, spewing out at the bottom of the glacier.

From a distance, a glacier may appear to be a flat sea of ice. Close up, features such as crevasses and even rivers, zig-zagging into the ice, become visible.

   Glacier Travel   

Hiking on a glacier lets you see these fascinating geologic sculptors close-up. Reading about the power of a glacier is one thing; hearing the distant cra-a-acks, as you walk across one, gives you a different feel for them.

Glacier travel presents special risks, particularly when snow-cover is present. A crevasse may be hidden under a layer of snow, waiting for an unwary hiker could break through. Anyone hiking on a snow-covered glacier should do so only with a guide, or suitable training, and in most cases should be part of a roped party.

Some glaciers, largely free of snow-cover, can be safely crossed without special training. Always get advice from local authorities before setting out on a glacier hike.

Rock climbing trips

Hiking trips

Hiking FAQs

Using your map and compass

Route-finding advice for hikers


Several trips offered by Alyson Adventures, which sponsors this site, include opportunities to get on a glacier:

Wild Kiwi, in New Zealand, includes an all-day hike, with an experienced guide, on one of the two largest glaciers in the country: Fox or Franz Josef glacier. Like most glaciers in temperate areas, these are choppy monsters, with giant blocks of ice spiking up at every angle.

In the Swiss Alps, on Edelweiss, you can cross Gornergletscher along the trail used by mountaineers, on their way to the Monte Rosa hut. Or ski here, on The Sound of Snowflakes.