the website you linked to does not list snowfall statistics at the tops of the mountains or for a 12 month (annual) period.
The point of choosing 6 months is to make comparisons between resorts valid. Many resorts including Big Sky measure less than six months in some or all years, so I have to project totals upward to get to 6 months. FYI Big Sky did measure all 6 months in 23 seasons and the raw average of those is 261 inches. Using more than 6 months would in most cases be irrelevant because October snow is usually melted out before the ski areas open, and very few areas are open after April 30. I do include May snowfall for a few areas consistently open then and will also count October snowfall if it's enough to advance an opening date or have a significant effect on what's open in November.
But it does not seem unreasonable to believe that a mountain that gets 258 inches of of snow in a six-month period at 8,903' might well get at least 400 inches of snow on top (11,145')
Actually that level of disparity from mid to top would be quite unusual, and I there is one exception I know. Jupiter Bowl 10,000 averages 394 inches while Summit House 9,200 averages 308 and the base of Park City 150. The difference between Jupiter and Summit House is not due so much to altitude as to Jupiter being close to the top of Brighton while the rest of Park City is well leeward of the crest of the Wasatch.
The statistic is repeated by many sources.
And there is zero basis for it, nada. If there were, there would be patrol data backing it up as there is with Jackson's new upper site. My source IS the patrol data. Big Sky like anyplace with the top far above tree line cannot measure accurately at the top due to wind exposure. You need a sheltered location. But what most skiers want is snowfall at representative elevation for where they are skiing. Big Sky's elevation range is 6,900 - 11,145. So 8,903 is a good representation, particularly since there's at least as much ski terrain below as above 8,903.
Last year the rocks were surfacing like school fish avoiding an attack.
There are always lots of rocks on Lone Peak. It's a recurring comment from nearly every visitor. In good years they are avoidable, but you always want to be alert up there because in many cases if you fall you are quite likely to hit something.
I always tell people to use common sense, observe their surroundings and believe what your own eyes and skis tell you. The comparison with Jackson is instructive in this case. Mid-mountain Jackson is 370 and mid-mountain Big Sky is 258. Temperatures and much of the topography are similar. Even the casual observer can notice the difference in snow coverage.
I am confused how there can be so much disagreement on quantity of snow.
Actually I'm a bit confused too. Small overstatements most people will not notice or let slide. But anyone who travels extensively knows what 400+ inch ski areas look like. Here's the short list of non-coastal ski areas between 370 and 430 inches: Brighton, Solitude, Whitewater, Wolf Creek, Steamboat, Fernie, Jackson.
Another interesting point that enhances the confidence in Big Sky snow data is that it's very consistent. Of the 23 years of complete Nov-Apr data the highest season is 342 inches and the lowest 174 inches, which is a very tight range. Standard deviation of winter (Dec-Mar) monthly snowfall as a percent of average is the second lowest in the West to Targhee. So while we may not expect to be buried in powder, the odds of a real disaster (where we dodged a bullet last year) are very remote.
The elevation at Big Sky and the north latitude generally guarantee a good snowpack into April
Along with the consistency of snowfall as noted above, so no argument there.
Edited by Tony Crocker - 9/30/12 at 12:14pm