Let's clear up some of the terms associated with downhill skiing. When put in the proper perspective, expert skiing is very different than advanced skiing or extreme skiing. The definitions below are based solely on our observations over the years, and are not cast in stone.
Expert skiing means being adept at handling varied terrain and different snow conditions on marked trails. The terrain may include steeps, trees, and moguls, or a combination of the three onblack or double-black runs. Snow conditions might include hard pack, ice, crud, or powder, as well as groomed or un-groomed snow.
Expert skiing requires that you make quick adjustments to your speed, turn radius, and balance to maintain control at all times. The challenge for the expert skier is to ski all the terrain in the descent of the mountain.
The essence of expert skiing is to be able to comfortably handle a run with a 40-degree pitch containing dense trees or tight moguls on un-groomed snow when there is no way out on either side.
The term advanced level skiing is usually reserved for the higher level steps or classes normally associated with ski school programs. Here, the terrain may consist of blue or black runs, widely-spaced glades, and smaller bumps on intermediate-level slopes.
In addition, snow conditions are normally hard pack and groomed. At this level you would be comfortable skiing mid-radius parallel turns on groomed hills.
This term is the domain of the daredevil. These guys are the ones in the Warren Miller movies. They normally ski off-piste and in the back country, but can also be seen dropping off of steep cliffs in the back bowls at some mountains.
I have the utmost respect for extreme skiers. They are one part tough, one part skilled, and one part courageous with a sprinkling of nuts thrown in for good measure. Extreme skiing is usually out-of-bounds skiing and risky, to say the least.