These are the levels of avalanche danger that follow the international 5-level standard:

LOW:
Natural avalanches are very unlikely, human-triggered avalanches are unlikely. Travel is generally safe in all terrain for travelers of all skill levels.

MODERATE:
Natural avalanches are unlikely, human-triggered avalanches are possible. Use caution in steeper terrain, especially on aspects identified in the avalanche advisory. Most, avalanche accidents occur in terrain rated as either moderate or considerable because people percieve that it's stable enough to get out into the backcountry, but there are just enough booby traps around to catch people. Use normal caution and safe-travel techniques while traveling in avalanche terrain--one at a time, never cross above your partners, have an escape plan in case you are caught by a slide and get out of the way at the bottom.

CONSIDERABLE:
Natural avalanches are possible, human-triggered avalanches are probable. Be increasingly cautious in steeper terrain. Most avalanche accidents occur in terrain rated as either moderate or considerable because it's stable enough to get out into the backcountry, but there are just enough booby traps around to catch people. Use normal caution and safe-travel techniques while traveling in avalanche terrain--one at a time, never cross above your partners, have an escape plan in case you are caught by a slide and get out of the way at the bottom.

HIGH:
Natural and human-triggered avalanches are likely. People without well developed avalanche skills should avoid avalanche terrain. Use all your usual techniques for staying out of trouble--stay out of run-out zones, stick to dense trees, low angle slopes and ridgelines away from cornices.

EXTREME:
Widespread natural or human-triggered avalanches are certain. Stay off of and out from under any terrain steeper than about 30 degrees. In extreme conditions, large avalanches can descend into mature forests and run beyond historic boundaries. Remember that unusual conditions produce unusual avalanches.