Glacier Terminology

Glaciers are incredibly dynamic formations of ice. At Kenai Fjords National Park, visitors may see and experience glacial features and landscapes they have never seen before. The following are some examples of these features with that are found in the park. Technical reference for terminology can be found from the National Snow & Ice Data Center (NSIDC) glossary, and U.S. Geological Survey (USGS) glossary.

 

Northwest Glacier at the head of Northwestern Fiord

NPS Photo/ D Kurtz

Glacier- a mass of ice that originates on land, usually having an area larger than one tenth of a square kilometer. Many believe that a glacier must show some type of flow or internal movement; others believe that a glacier can show evidence of past or present movement.

 

The Harding Icefield above Tustamena Glacier.

NPS Photo

Icefield- a large area of interconnected glaciers. Icefields form in colder climates and higher altitudes where there is enough precipitation for them to form.

 

Exit Glacier in 2016

NPS Photo/ D Kurtz

Valley Glacier- a glacier whose flow is confined by valley walls and flows through a valley.

 

An aerial image of Aialik Glacier flowing into Aialik bay.

NPS Photo/ D Kurtz

Tidewater glacier- a glacier that terminates in the ocean.

 

A cirque glacier on the side of a mountain.

NPS Photo/ D Kurtz

Cirque glacier- a glacier that occupies basins near ridge crests. Most cirque glaciers have a characteristic circular shape, with their width as wide or wider than their length.

 

A hanging glacier flows over the top of a mountain in Holgate Arm and ends on the mountainside.

NPS Photo/ A Collins

Hanging glacier- a glacier that terminates at or near the top of a cliff. They sometimes appear to be hanging from the cliffside. Hanging Glaciers sometimes look like frozen waterfalls.

 

The terminus of Exit Glacier and its meltwater stream

NPS Photo/ A Collins

Drift- all types of sediment deposited by a glacier, regardless of the size or amount of sorting. The term includes all sediment that is transported by a glacier, whether it is deposited directly by a glacier or indirectly by running water that originates from a glacier.

 

Resurrection River outwash plain

NPS Photo/ D Kurtz

Outwash Plain- A broad, low-slope alluvial plain. Outwash plains are composed of glacially eroded and sorted sediment that we call outwash. This outwash has been transported by meltwater from the glacier. The outwash plain begins at the foot of a glacier and may extend for miles. Typically, the sediment becomes finer grained the further one gets from the glacier terminus.

 

Glacial Till- Sediment material that has been directly deposited by glacier ice. Glacial till is mixed together, it is not sorted or layered by size.

 

Moraine- a mound, ridge, or other distinct accumulation of glacial till.

 

Medial moraine on Bear Glacier

NPS Photo/D Kurtz

Medial moraine- a ridge-shaped moraine in the middle of a glacier originating from a rock outcrop, nunatak, or the converging lateral moraines of two or more ice streams.

 

Lateral moraines along Sunset Glacier.  Parts of the lateral moraines are vegetated.

NPS Orthophoto from 2016

Lateral moraine- a ridge-shaped moraine deposited at the side of a glacier and composed of material eroded from the valley walls by the moving glacier.