These warnings apply primarily to the road conditions, whilst differentiating between the following hazards:

• Slippery conditions due to packed snow: Snow that has frozen solid on the roads (up to 4 cm thick)
• Black ice: Wet roads which subsequently freeze over as a result of clear skies at night
• Icy roads: Cold or cooled precipitation (freezing rain/drizzle/fog precipitation) that falls onto a road sur-face with a temperature below 0 degrees, thus freezing solid instantly
• Rime ice: High levels of moisture that freezes on supercooled road

Hazard level 5 (very severe hazard)

Widespread ice formation on roads over a sustained period is a rare occurrence in Switzerland.

Danger levels 4 (severe danger)

Hazard category 3 (significant hazard)

Hazard category 2 (moderate hazard)

Recommendations for action

Recommendations during slippery roads

Notes

Warnings of slippery conditions are issued up to 800 m above sea level on the northern side of the Alps and up to 1600 m above sea level on the southern side of the Alps.