Flood: Return period of more than 50 years.
• Expected many landslide events, several with considerable consequences.
• Extensive flooding, erosional damage and flood damage to buildings and infrastructure.
Flood: Return period of more than 5 years
• Expected many landslide events, some with considerable consequences.
• Extensive flooding, erosional damage and flood damage to certain prone areas.
• Expected some landslide events, certain large events may occur.
• Local flooding and/or erosional damage due to rapid increase of discharge in streams/ small rivers, ice drift, ice in streams/rivers and frozen soil.
• High flow/water level in comparison to normal seasonal variations.
• Discharge close to orange level.
N.B.: The extent of damage relates to a combination of the vulnerability (i.e., infrastructure and other potential damage) in the warning area and the awareness level – not solely to the awareness level.
A flood warning indicates risk of flooding of rivers and lakes:
A landslide warning indicates risk of debris avalanches, debris floods and/or slush slides:
Slush slides: A stream of waterlogged snow. These landslides can start in relatively flat terrain and seek towards streams and steep slopes.
Quick clay landslides and some mudslides are caused by processes that have very slow effective response or human activity, and are not included in landslide early warning.
A forecast for heavy rain (torrential rains) from the Meteorological Institute, developed in cooperation with NVE, indicates local and momentary risk of:
Surface runoff, storm water in urban areas, local flooding, local flash floods with erosional damage, debris flows and debris floods where the rainfall occurs.
In the case of issued both flood and landslide warnings, please note:
• The warnings can be valid for different areas even though they are issued for the same period.
• The warnings may have different durations even though they are issued for the same area.