Now here is another thought: How deep is too deep?
The main differences I notice when skiing powder on skis of various widths is speed and recovery time between turns. A narrower ski sinks deeper into the snow (if you are lucky enough to have true powder - which to my mind is a fluffy layer of 8" to knee deep on top of a soft subsurface) At some point the ski will rebound off the subsurface and allow you to crank out the next turn. With a fatter ski, the skis are ready for that next turn much sooner. They can feel more maneuverable. They don't sink in as deeply so you can experience "bottomless" conditions in relatively shallow pow, depending on slope angle. In can be fun to ski in four inches of snow and not feel the subsurface on low angle slopes.
A side effect of the skis not sinking and rising thru as much distance is that there is less "porpoise-ing" which may be something you will miss. The skis running closer to the surface also run much faster. There is less drag against your legs. So if you want to crank and bounce out the maximum turns per pitch (aka Utah machine track) stick with the narrower models. If you want to haul ass and skim the surface with longer turns - go big or go home.
Having said all that, I think that skis are currently flirting with excessive width. IMHO skis that are over 100mm at the waist will be too much except for those days where there is too much of a good thing, around 3 feet of fresh snow and slopes that are long enough and steep enough to give you room to fly while still being safe enough to ski without avalanche. Rare conditions that often come in conjunction with road closures. If you are into helicopter skiing and professional level extreme skiing rock on!
There is a reason that those skis are called "Big Mountain" skis. You just don't take your rocket ship to the corner grocery store. Sadly, whopping big skis are a way to become bored with your local hill, even if it was formerly challenging.
Powder skis come in two varieties, for finese and power skiing. The later skis being stiffer and wider. Some powder skis will feel easier to ski than a hard snow carver others will feel like armored personnel carriers. There is a lot of room between 74mm and 130mm.
- Mark, SLC