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Current rain hazards

Updated on: 28.08.2016, 20:29

Current rain hazards in Switzerland

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Rain: No or minor danger, level 1

Kontextspalte

Danger level 1 (No or minor danger)
Danger level 2 (Moderate danger)
Danger level 3 (Considerable danger)
Danger level 4 (High danger)
Danger level 5 (Very high danger)
No danger level
Danger level 1 (No or minor danger)

Rain warnings are only issued for the danger levels 2 - 5.

Danger level 2 (Moderate danger)
  • Effects: Local swelling of streams or local flooding possible in areas where the ground is already saturated
  • Behaviour: Keep an eye on local weather developments, and act appropriately, according to the information you  receive on the conditions
  • Description of measurement and prognostic values:
    • Sustained rainfall north of the Alps and in the Alps: 30-50 mm/24 h
    • Sustained rainfall south of the Alps and in Simplon: 70-100 mm/24 h
    • Sustained rainfall in Verbano, Valle Maggia: 100-150 mm/24
Danger level 3 (Considerable danger)
  • Effects:
    • Swelling of streams, waterfalls and normally dry ditches, and flooding of exposed cave systems;
    • Disruption to road traffic on exposed stretches
  • Behaviour:
    • Keep an eye on local weather developments
    • Stay away from water (as well as dry river or stream beds) and from shores and river banks
    • Avoid steeply sloping terrain
    • Always follow the official recommendations
  • Description of measurement and prognostic values:
    • Sustained rainfall north of the Alps and in the Alps: 50-80 mm/ 24 h, 80-110 mm/48 h, 100-130 mm/72 h
    • Sustained rainfall south of the Alps and in Simplon: 100-130 mm/24 h, 130-160 mm/48 h, 160-200 mm/72 h
    • Sustained rainfall in Verbano, Valle Maggia: 150-200 mm/24 h, 200-250 mm/48 h, 250-300 mm/72 h
Danger level 4 (High danger)
  • Effects:
    • Potential for rivers to overflow onto floodplains and flood zones as well as around lake shores.
    • Heavily swollen streams, waterfalls and normally dry ditches, and flooding of cave systems;
    • Potential for localised landslides on steeply sloping terrain;
    • Failure of drainage and sewer systems;
    • Flooding of underpasses, underground garages and cellars/basements;
    • Disruption to road and rail traffic.
  • Behaviour:
    • Keep an eye on local weather developments
    • Stay away from water (as well as dry river or stream beds) and from shores and river banks
    • Avoid steeply sloping terrain
    • Always follow the official recommendations
  • Description of measurement and prognostic values:
    • Sustained rainfall north of the Alps and in the Alps: 80-120 mm/24h, 110-150 mm/48h, 130-170 mm 72h
    • Sustained rainfall south of the Alps and in Simplon: 130-160 mm/24 h, 160-200 mm/48 h, 200-240 mm/72 h
    • Sustained rainfall in Verbano, Valle Maggia: 200-250 mm/24 h, 250-300 mm/48 h, 300-350 mm/72 h
Danger level 5 (Very high danger)
  • Effects:
    • Flooding, even in areas which are not usually prone to flooding;
    • Extreme swelling of streams, waterfalls or normally dry ditches, even in areas which are normally at low risk;
    • Failure of drainage and sewer systems and flood protection barriers;
    • Flooding of underpasses, underground garages and cellars/basements;
    • Massive disruption to road and rail traffic;
    • High likelihood of landslides on sloping terrain and mudslides.
  • Behaviour:
    • Keep an eye on local weather developments
    • Stay away from water (as well as dry river or stream beds) and from shores and river banks
    • Avoid steeply sloping terrain
    • Always follow the official recommendations
  • Description of measurement and prognostic values:
    • Sustained rainfall north of the Alps and in the Alps: >120 mm/24 h, > 150 mm/48 h, >170 mm/72 h
    • Sustained rainfall south of the Alps and in Simplon: >160 mm/24 h, > 200 mm/48 h, >240 mm/72 h
    • Sustained rainfall in Verbano, Valle Maggia: >250 mm/24 h, > 300 mm/48 h, > 350 mm/72 h
No danger level

No evaluation