Red List habitat classification > RLC - Freshwater habitats > RLC1.7 Permanent lake of glaciers and ice sheets

Permanent lake of glaciers and ice sheets

Quick facts

Red List habitat type code RLC1.7
Threat status
Europe Data Deficient
EU Vulnerable
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


Glacier lakes are formed as a consequence of melting of a glacier or icesheet, typically bordering to melting glaciers. In some cases these waterbodies can occur under the glacier. Glacier lakes are formed in depressions or crevices filled by melting water. In areas without depressions melting water runs as subglacial brook or river, and later discharges to alpine brooks or rivers (type C2.2a, and C.3.5d). Glacier lakes are often dammed by a rock threshold or a moraine ridge. If water volume increases, the lake can outburst through the damming.

Permanent or almost permanent ice formations are characteristics of glacier lakes, constituting of continuous ice sheets that may cover the entire surface for all the year or recede to part of the lake during summer, being accompanied or replaced by floating ice blocks. They may locally, seasonally or permanently, extend to the whole depth of the lake. Glacier lakes are mainly abiotic environments. Benthic and planktonic microalgae form ultraoligotrophic communities consisting of cold-adapted species; usually lakes are without any higher vegetation. If high mountain lakes or brooks are nearby, some aquatic mosses, macroalgae and macroinvertebrates may invade glacier lakes. In some cases also fish and waterfowl spreads to glacier lakes, particularly in water bodies on lower elevation or in coastal areas. A good example is the Jökulsárlón glacier lagoon in Iceland where fishes drift in from the sea along with the tides. Glacier lakes are also in contact with various other arctic and alpine habitats, usually unvegetated or with very sparse vegetation. Typical adjacent habitats are rocks, screes, boulder and gravel fields, moraine ridges or sandur-formations. Permanent glacier lakes occur in Europe only in a few countries, a majority of them in Iceland and Norway, Because of the small size of glaciers in the Alps the habitat is very rare there.

Water bodies can also be formed under the glacier. A special type of these water bodies occurs in Iceland where large glaciers (particularly Vatnajökull) lie above active volcanoes. Volcanic activity can melt large quantities of water under the ice, resulting in large-scale outburst of melting water with mud, gravel and stone. Several glacier lake outburst floods (GLOFs) are known from Iceland during the last centuries. An example is the outburst of the volcano Grimsvötn, situated under the Vatnajökull ice cap, in the 1990s. Also Myrdalsjökull is famous for these catastrophic events, called jökulhlaup in Icelandic.

Indicators of good quality:

  • Long-term stable hydrology, reflected in a balance between accumulation of ice and melting of the glacier

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

Limited data were available for this habitat type. There were no territorial data from Iceland and Norway, the countries with most occurrences of the habitat in EU28+. For the EU28+ the habitat has been assessed as Data Deficient (DD) due to the lack of information. However, by assuming the quantitative data from Switzerland to be representative for the Alps and because of the few occurrences there, for the EU28 the habitat is assessed to be Vulnerable (VU) because of decline in area and quality, and a small distribution area in combination with threats and declines.
Red List Category Red List Criteria
Vulnerable A1, B2, C/D1, C1
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Human intrusions and disturbances
    • Outdoor sports and leisure activities, recreational activities
  • Pollution
    • Air pollution, air-borne pollutants
  • Natural System modifications
    • Human induced changes in hydraulic conditions
  • Geological events, natural catastrophes
    • Volcanic activity
  • Climate change
    • Temperature changes (e.g. rise of temperature & extremes)

Habitat restoration potential


Trends in extent

Average current trend in quantity

Decreasing Unknown
EU28 EU28+

Trends in quality

Average current trend in quality

Decreasing Unknown
EU28 EU28+

Conservation and management needs

In the longer term survival of glacier lakes is dependent on the existence of glaciers. That requires mitigation of effects of climate change already in the near future. Input of CO2 and other greenhouse gases is the main driver in the climate change, therefore mitigation of these gases is essential.

List of conservation and management needs

  • No measures
    • Measures needed, but not implemented


For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

EU28 Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Austria Present Unknown Stable Stable
Italy mainland Uncertain Unknown Unknown Unknown
Sweden Uncertain Unknown Unknown Unknown
France mainland Uncertain Unknown Unknown Unknown
EU28 + Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Iceland Present Unknown Unknown Unknown
Norway Mainland Present Unknown Unknown Unknown
Svalbard Present Unknown Unknown Unknown
Switzerland Present <1 Unknown Decreasing

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 2038650 Unknown Unknown EOO is potential range
EU28+ Unknown Unknown EOO is potential range
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

This habitat may be equivalent to, or broather than, or narrower than the habitats or ecosystems in the following typologies.
Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200711 C1.7 Permanent lake ice same
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