Ski Areas Indifferent to El Nino/La Nina
On my El Nino page I introduced the Multivariate ENSO Index , which is considered by many meteorologists to be the best overall measure of the strength of El Nino/La Nina. The graph of MEI since 1950 is repeated here for convenience.
The last posted value of MEI as of 11/21/2007 is -1.117 for SEP/OCT 2007, and we have quite strong confidence that observed La Nina condition will be in effect through the end of 2007, and some confidence that it will persist for the entire 2007-08 ski season.
I have correlated the monthly MEI table with all of the monthly snowfall data I have collected through 2007. The list of ski areas insensitive to El Nino/La Nina, along with their monthly and season correlations to the MEI index, is shown below:
| Area | Monthly | Seasonal | Seasons |
| Minimal sensitivity to El Nino/La Nina | |||
| Sugar Bowl, Calif. 7,000 | 13.2% | ||
| Monarch, Colo. | 10.2% | ||
| Heavenly Valley, Calif. 8,400 | 7.1% | 32.4% | 23 |
| Wolf Creek, Colo. 10,642 | 7.1% | ||
| Alpine Meadows, Calif. 7,000 | 6.7% | 18.4% | 38 |
| Heavenly Valley, Calif. 10,000 | 6.2% | ||
| Loveland, Colo. 11,200 | 5.8% | 3.9% | 27 |
| Snowshoe, W. V. 4,848 | 5.6% | ||
| Arapahoe Basin, Colo. 10,820 | 5.3% | 9.7% | 21 |
| Central Sierra Snow Lab - Boreal, Cal. 7 | 5.1% | 15.1% | 42 |
| Kirkwood (Carson Pass), Calif. 8,526 | 4.8% | 14.7% | 34 |
| Squaw Valley, Calif. 8,000 | 4.5% | ||
| Sun Valley, Idaho 8,800 | 4.3% | ||
| Winter Park Base, Colo. 9,265 | 3.4% | 0.0% | 15 |
| Mt. Rose, Nev. 8,600 | 3.2% | ||
| Red Mt. Pass, Colo. 11,090 | 2.9% | -13.8% | 18 |
| Remarkables, New Zealand 5,203 | 2.8% | -4.4% | |
| Mt. Hutt, New Zealand 4,602 | 2.3% | 1.9% | |
| Purgatory, Colo. 10,000 | 1.5% | ||
| Aspen Mtn, Colo. 11,190 | 1.4% | ||
| Sugarloaf, Maine 3,695 | 0.8% | 5.9% | 42 |
| Squaw Valley, Calif. 6,200 | 0.7% | -46.5% | 18 |
| Mary Jane at Winter Park, Colo. 10,80 | -0.3% | 1.4% | 33 |
| Red Mt. 2, B. C. 6,650 | -0.7% | ||
| Beaver Creek, Colo. 11,200 | -1.0% | ||
| Telluride, Colo. 11,170 | -1.3% | ||
| Big Sky, Mont. 8,920 | -1.7% | -15.2% | 17 |
| Alyeska, Alaska 1,400 | -1.8% | 1.8% | 26 |
| Northstar, Calif. 7,800 | -2.8% | ||
| Alta, Utah 8,650 | -2.9% | -0.3% | 40 |
| Coronet Peak, New Zealand 4,032 | -2.9% | ||
| Vail, Colo. 11,250 | -2.9% | -10.5% | 14 |
| Sunlight, Colo. | -3.0% | ||
| Mt. Washington, B. C. 3,926 | -3.1% | ||
| Berthoud Pass, Colo. 11,315 | -3.3% | -6.4% | 36 |
| Gothic, Colo. 9,400 | -3.3% | -2.5% | 32 |
| Killington, Vt. 4,142 | -3.4% | -6.8% | 42 |
| Waterville Valley, N. H. 3,000 | -4.3% | ||
| Snow Basin, Utah 7,700 | -4.6% | ||
| Brighton, Utah 8,740 | -4.8% | -7.7% | 36 |
| Blackcomb, B. C. 5,002 | -5.3% | -8.4% | 17 |
| Keystone, Colo. 11,641 | -5.4% | ||
| Mt. Snow, Vt. 3,600 | -5.6% | ||
| Copper Mtn, Colo. 11,000 | -5.7% | ||
| Park City 2, Utah 9,280 | -5.8% | -2.5% | 30 |
| Stratton, Vt. 3,875 | -5.9% | 11.9% | 19 |
| Whistler Roundhouse, B. C. 6,000 | -6.0% | -3.3% | 29 |
| Whiteface (Lake Placid), N. Y. 3,660 | -7.2% | ||
| Crested Butte, Colo. 10,150 | -9.4% | ||
| Mt. Washington, N. H. 6,262 | -9.5% | -19.0% | 42 |
| Sugarbush, Vt. 3,000 | -10.4% | -6.7% | 21 |
| Whitewater, B. C. 5,500 | -11.1% | ||
| Breckenridge, Colo. 11,100 | -11.3% | ||
| Snowbird, Utah 10,000 | -11.5% | -20.8% | 35 |
| Deer Valley, Utah 8,200 | -12.0% | ||
| Crystal Mtn 2, Wash. 6,100 | -12.4% | ||
| Grand Targhee, Wyo. 8,200 | -13.0% | -26.5% | 32 |
| Aspen Highlands, Colo. 11,100 | -14.0% | ||
| Crystal Mtn 1, Wash. 4,400 | -14.6% | ||
| Jupiter Bowl, Utah 10,000 | -14.8% | -16.3% | 20 |
| Brighton/Solitude, Utah 9,400 | -15.0% | ||
| Snowmass, Colo. 11,000 | -15.0% |
Note that there are 62 areas listed here, vs. 10 that are favored by El Nino and 31 favored by La Nina. In particular, with the exceptions of Brian Head and Steamboat El Nino/La Nina have minimal predictive value for Utah and Colorado ski areas.
In the El Nino favored page I analyzed the data from Donner Pass near Lake Tahoe, illustrating that Tahoe area snowfall is not as sensitive to El Nino as most people think. The most southwestern locations in Colorado like Purgatory, Telluride and Red Mt. Pass (also presumed by many to be favored by El Nino) have even smaller correlations than North Tahoe.
Most Northern Rockies areas are favored by La Nina, but there are a few microclimates that are less sensitive. First would be Grand Targhee, which is the most consistent area that I track and doesn't seem sensitive to anything. Sun Valley and Sun Peaks have fairly dry climates that are blocked out of some prevailing weather patterns. It is well known that Sun Valley gets its biggest dumps from the south, and the record El Nino of 1983 was its second highest snow season. I suspect Red Mt. favors El Nina quite strongly even though it doesn't show up in my relatively sketchy data for the area. Big Sky's insensitivity is the other surprise, although Big Sky's weather tends to be independent of other areas, and nearby Bridger Bowl is favored by La Nina.
In the La Nina favored page I noted that the Whistler alpine and New Zealand are not as sensitive to La Nina as many people assume.
And finally, the Northeast is not particularly affected by El Nino/La Nina.
I have constructed graphs to illustrate the variability of the snowfall correlations to El Nino/La Nina. The one below is for selected areas with minimal sensitivity to El Nino/La Nina.
The areas above were selected for complete data over 42 years. Berthoud Pass (yellow line) is a good representative for the numerous areas along the I-70 corridor in Colorado, ranging west to Aspen. Killington (orange) and Mt. Washington (light blue) represent a couple of climate zones in the Northeast.
If you look at the 6 strongest El Nino and La Nina seasons, Alta (purple), Berthoud, Mt. Washington and Killington all have at least 2 above average seasons and 2 below average seasons.
Overall the graph shows why El Nino and La Nina do not predict snowfall well for the 62 areas listed in the Minimal Sensitivity list above.