American and European avalanche danger scales rate avalanche hazard similarly with the exception of using slightly different colours.

 LOW

• Backcountry travel is fairly safe.
• Natural or human-triggered avalanches unlikely.
• Only isolated areas of instability.
• Snowpack is generally stable.

MODERATE

Yellow in both American and European scales:

• Backcountry travel possible with caution.
• Natural avalanches unlikely; human-triggered avalanches possible.
• Some areas of instability.

CONSIDERABLE

Orange in American scale,
Ochre in European scale:

• Backcountry travel possible with extreme caution.
• Natural avalanches possible; human-triggered avalanches probable.
• Unstable areas probable.

HIGH

Red in American scale,
Orange in European scale:

• Backcountry travellers should avoid steep slopes and wind-loaded slopes.
• Natural and human-triggered avalanches highly likely.
• Unstable areas highly likely on various slopes and aspects.

EXTREME

Black in American scale,
Red in European scale:

• Backcountry travellers should avoid any steeply angled terrain or known
  avalanche areas.
• Extremely unstable layers in snowpack.
• Large destructive avalanches probable.
• Natural and human-triggered avalanches are certain.