The History of Southern California Snow Conditions chart is the best expression I've devised for displaying the range and incidence of snow conditions. In order to construct such a chart it is necessary to have week by week reports of conditions. While I do not have enough reports for Colorado, I have tracked the percent of terrain open in early season for several years, and found that information for prior years going back to 1988. So I've constructed a chart of 25th, 50th and 75th percentiles for a "Colorado Profile." The early season is based primarily on the Breckenridge and Copper Mt. terrain open stats, but would be applicable to other Colorado areas in the typical 250-300 inch snowfall range. The late season is also based mostly upon Front Range/Summit County. I show some medians for areas that differ from the "Colorado Profile" and explain them below.
The focus of these charts is to show coverage of terrain and
frequency/consistency of packed powder snow that has not been
through a melt/freeze. The weekly grades
are not a measure of fresh powder, which cannot be predicted in advance
for a specific week. In 2008 I derived a method to estimate percent of
powder days from monthly snowfall. I now apply that percentage to all
weeks rated A or B and show that percentage and an adjusted
total grade at far right. For details, see What Is
the Probability of a Powder Day?
.
Definitions:
| A: |
| B: |
| C: |
| D: |
| PROFILE OF COLORADO SNOW CONDITIONS | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Pwdr Adj | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Season/Month | October | November | December | January | February | March | April | May | June | Total | A | B | C | Pwdr | Total | |||||||||||||||||||||||||||||||||||||||||||||
| 75th percentile | 0 | D | D | C | 1 | C | C | B | B | A | 9 | A | A | A | A | 12 | A | A | A | A | 12 | A | A | A | A | A | 15 | A | A | A | 9 | 0 | 0 | 58 | 17 | 19 | 22 | 13% | 70 | |||||||||||||||||||||
| Median | 0 | D | D | D | 0 | D | C | C | B | B | 6 | B | A | A | A | 11 | A | A | A | A | 12 | A | A | A | A | A | 15 | A | A | B | 8 | 0 | 0 | 52 | 14 | 18 | 20 | 11% | 61 | |||||||||||||||||||||
| 25th percentile | 0 | D | D | D | 0 | D | D | C | C | C | 3 | B | B | B | A | 9 | A | A | A | A | 12 | A | A | A | A | B | 14 | A | B | B | 7 | 0 | 0 | 45 | 10 | 16 | 19 | 9% | 51 | |||||||||||||||||||||
| A-Basin Median | D | 0 | D | D | D | D | 0 | D | D | C | C | B | 4 | B | B | A | A | 10 | A | A | A | A | 12 | A | A | A | A | A | 15 | A | A | A | B | 11 | B | B | C | C | 6 | C | 1 | 59 | 14 | 20 | 25 | 11% | 68 | |||||||||||||
| Vail Median | 0 | D | C | 1 | C | B | B | A | A | 11 | A | A | A | A | 12 | A | A | A | A | 12 | A | A | B | A | B | 13 | A | B | B | B | 9 | 0 | 0 | 58 | 14 | 21 | 23 | 15% | 71 | |||||||||||||||||||||
| Steamboat Median | 0 | D | C | 1 | B | B | A | A | A | 13 | A | A | A | A | 12 | A | A | B | A | 11 | B | A | B | A | B | 12 | B | B | 4 | 0 | 0 | 53 | 12 | 20 | 21 | 15% | 64 | |||||||||||||||||||||||
| Jackson Median | 0 | 0 | C | C | B | B | A | 9 | A | A | A | A | 12 | A | B | A | B | 10 | B | A | B | C | B | 10 | C | 1 | 0 | 0 | 42 | 8 | 15 | 19 | 17% | 51 | ||||||||||||||||||||||||||
| Taos Median | 0 | D | D | 0 | D | D | C | C | C | 3 | B | B | B | A | 9 | A | A | A | A | 12 | A | A | A | A | A | 15 | A | 3 | 0 | 0 | 42 | 11 | 14 | 17 | 10% | 48 | ||||||||||||||||||||||||
| Taos 05-06 | 0 | 0 | D | D | D | D | 0 | D | D | C | C | C | 3 | C | C | C | C | 4 | B | A | A | A | 11 | A | 3 | 0 | 0 | 21 | 4 | 5 | 12 | 7% | 23 | |||||||||||||||||||||||||||
| Vail 2011-12 | 0 | D | D | 0 | D | D | C | C | 2 | D | D | C | C | B | 4 | A | A | A | A | 12 | A | B | C | C | C | 8 | D | D | 0 | 0 | 0 | 26 | 5 | 7 | 14 | 9% | 29 | |||||||||||||||||||||||
Results:
The "Colorado Profile" is strongly skewed to favor late season.
The light and dry snow does not on average get the steepest terrain
covered until early January. But the snow preserves superbly at
altitudes as high as 12,000 feet. Predominantly north facing
terrain and a strong spring snowfall pattern can result in nearly
continuous winter surface conditions up to April closing dates. The
profile most closely fits Copper Mt., though it also fits Aspen and
Telluride, except for their earlier closing dates due to greater
distance from the Denver locals.
Colorado has numerous areas that differ from the "Profile" in one way or another, and I show medians for 3 of them. A-Basin is the profile enhanced. Despite more snowfall, its steeper than average terrain is even slower to get covered than other Colorado areas. The runs open in October are just a couple with snowmaking. The altitude and spring snowfall are even better than the profile, and combined with its proximity to Denver A-Basin will stay open until its snow runs out. The range of closing dates is similar to Mammoth's, though the steep Pallavicini terrain will close earlier than Mammoth's more stable snowpack steeps.
Vail's 350 inch snowfall average makes a big difference in early season, as its Back Bowls are open by Christmas in 80+% of seasons. The bowls will go to spring conditions in sunny weather as early as February, while Blue Sky Basin and most of the frontside have excellent preservation typical of the profile. So the chart starts the spring conditions "checkerboard" in mid-March as a blend.
Steamboat gets even more snow than Vail and has one of the best early season records anywhere, close to Alta and Whistler in reliability. But the area faces more south than north, so the spring conditions "checkerboard" starts in February. Steamboat can be considered the "anti-profile" area of Colorado.
Other Areas :
A couple of other areas can be considered blends of the examples
above. Winter Park gets about the same amount of snow as Vail and
has a similar early season, while it has the snow preservation of
the profile. Breckenridge is the converse, with profile snowfall
and early season, but with mainly east exposure the spring range of
conditions on most of the mountain is more like Vail. However, about 20%
of Breckenridge is very high and preserves as well as A-Basin.
I also show medians for two of the most extreme areas of the West. Extreme is an apt adjective, because steep ungroomed areas like Jackson Hole and Taos are more sensitive to issues of coverage and surface conditions. Jackson has abundant snowfall but with predominantly southeast exposure has difficult surface conditions in warm weather. Thus the spring "checkerboard" starts in February, and from mid-March onwards the grade will sometimes be C because some terrain will be unskiable without fresh snow.
Taos is the Colorado profile in extreme, as it's steeper than A-Basin and thus takes even longer to get covered. And it has perfect altitude/exposure for snow preservation, though it closes in early April due to remote location, often with its best conditions of the season. An enterprising ski bum should find a way to work in Jackson through early February and after that in Taos.
Drought Seasons :
The western drought year of 1976-77 was almost as
severe in most of Colorado as in the Sierra. And 1980-81 was as bad
in Colorado though it was much less severe in other western
regions. Most of the "profile" areas had less than 90 inches
snowfall through the end of February in both of these seasons,
implying a season score of 20-25 (before powder adjustment). Those two
seasons prompted most Colorado destination resorts to install snowmaking
around their base facilities and on busy trails.
Taos' 2005-06 season is a good surrogate for what 1976-77 and 1980-81 would have been like in many Colorado areas due to similar snowfall pattern, with most of the snow coming very late in the season. Areas with more intermediate terrain and the upgraded snowmaking would now score 25-30 in a year like this. 1989-90 was similar to the 2 earlier seasons in southern and western Colorado, but from Vail east there was a December dump that made a big difference for the northern and central areas.
2011-12 was the record low season at Winter Park and Loveland and as bad as 1976-77 and 1980-81 along the I-70 corridor. Vail's 2011-12 season is shown accordingly. The early season drought did not last quite as far into the new year, but March was record dry and much terrain melted out and closed prematurely during what is normally the most reliable ski month in the region.
Winter Park and Steamboat get more consistent snow and so can fare somewhat better, as Winter Park did in 1980-81 and Steamboat in 2011-12. Other Colorado areas can be viewed as having at least a 5% risk of drought/marginal coverage into mid-season. The risk is more like 10% in the southern and western areas, and probably at least 15% at Taos and Crested Butte, which have a disproportionate amount of steep terrain requiring more coverage.
More Snow Conditions Charts
Vermont
Fernie and Whistler
Mammoth/Sierra Nevada
Utah