Ski Areas Favored by La Nina (as of 2016)
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.
When I first wrote this article on 11/21/07 the last posted value of MEI was -1.117 for SEP/OCT 2007, and I expressed strong confidence that the observed La Nina condition would be in effect through the end of 2007, and some confidence that it would persist for the entire 2007-08 ski season. It turned out that La Nina remained strong (2007-08 was 5th highest La Nina in the past 50 years) through FEB/MAR, then dissipated over the next 3 months to a neutral value of +0.050 as of MAY/JUN 2008. Similarly the El Nino of 2009-10 was strong through FEB/MAR (the 7th highest El Nino in the past 50 years), but MEI turned negative by MAY/JUN. By AUG/SEP 2010 MEI registered -1.99, the strongest La Nina reading since 1955. The La Nina of 2010-11 remained strong through MAR/APR (the 2nd highest La Nina in the past 50 years) before weakening abruptly in APR/MAY 2011. La Nina strengthened to a moderate level for fall 2011 and gradually weakened starting JAN/FEB 2012. The MEI Index did not have a sustained significant El Nino or La Nina stretch for the next 3 ski seasons. The 2015-16 El Nino exceeded +2.0 for all but one month from MAY/JUN 2015 through MAR/APR 2016 and is the 3rd highest in the past 50 years. The northern spring months are the historically most likely time for an El Nino or La Nina to break up, as occurred for all 4 events from 2007-2012. The 2015-16 El Nino showed its first major sign of weakening in MAY/JUN, falling to +1.029.
I have correlated the monthly MEI table with all of the monthly snowfall data I have collected through 2016. The list of ski areas favored by La Nina, along with their monthly and season correlations to the MEI index and average snowfall during strong El Nino and La Nina months, is shown below:
|El Nino||La Nina|
|Strongly favored by La Nina|
|Big Mountain, Mont. 6,700||-29.0%||75%||120%|
|Castle Mt., Alb. 5,700||-25.8%|
|Snoqualmie Pass, Wash. 3,000||-24.8%||-55.9%||50||79%||132%|
|Mt. Baker, Wash. 4,300||-21.4%||-52.7%||26||87%||132%|
|Fernie Snow Valley, B. C. 5,400||-19.5%||-52.6%||27||79%||117%|
|Mt. Hood Meadows, Ore. 5,400||-19.7%||-52.6%||27||81%||131%|
|Jackson Hole, Wyo. 8,250||-23.1%||-52.5%||49||91%||122%|
|Sunshine Village, Alb. 7,028||-23.5%||-51.0%||46||87%||120%|
|Mt. Fidelity (Selkirks), B. C. 6,150||-21.0%||-49.7%||47||89%||116%|
|Silver Star, B. C. 5,200||-24.2%||-48.9%||18|
|Mt. Rainier Paradise, Wash. 5,420||-23.6%||-47.3%||50||86%||125%|
|Whistler Base, B. C. 2,200||-24.9%||-46.1%||39||83%||142%|
|Steamboat, Colo. 9,200||-18.5%||-38.2%||35||87%||112%|
|Schweitzer, Idaho 4,700||-22.4%||86%||129%|
|Bridger Bowl, Mont. 7,100||-23.0%||86%||111%|
|Teton Pass, Wyo. 8,000||-21.3%|
|Mt. Bachelor, Ore. 6,350||-19.3%||-35.6%||43||90%||131%|
|Cannon Mt., N. H. 1,800||-20.3%||-38.8%||40||86%||119%|
|Lake Louise, Alb. 6,700||-17.7%||-37.3%||47||88%||113%|
|Stevens Pass, Wash. 4,062||-18.2%||80%||119%|
|Mt. Norquay, Alb. 5,350||-16.3%||-32.7%||20||82%||114%|
|Crystal Mtn 2, Wash. 6,100||-14.0%||90%||124%|
|Mildly favored by La Nina|
|Smuggler's Notch, Vt. 1,600||-21.9%||-54.0%||23||75%||96%|
|Brundage, Idaho 6,000||-31.9%||28|
|Snowmass, Colo. 11,000||-15.2%||86%||107%|
|Grand Targhee, Wyo. 8,200||-16.8%||-34.2%||40||96%||114%|
|Crater Lake (Mt. Bailey), Ore. 6,800||-14.5%||-30.1%||50||95%||123%|
|Crystal Mtn 1, Wash. 4,400||-15.5%||84%|
|Whitewater, B. C. 5,500||-14.4%||93%||117%|
|Jupiter Bowl, Utah 10,000||-14.8%||-18.7%||28||95%||113%|
|Jay Peak, Vt. 3,000||-17.2%||-35.2%||35||85%||102%|
|Big Sky, Mont. 8,920||-17.4%||-43.7%||30||94%||113%|
|Crested Butte, Colo. 10,150||-14.6%||87%||110%|
|Brighton/Solitude, Utah 9,400||-21.9%|
|Mansfield Stake, Vt. 3,950||-16.8%||-33.8%||50||86%||104%|
|Sugarbush, Vt. 3,000||-16.8%||-22.4%||29||75%||90%|
|Loon, N. H. 2,000||-16.4%|
|Mt. St. Anne, Que. 2,000||-15.7%|
|Spencer's Creek, Australia 5,903||-23.6%||60|
Recall from before that these correlations fit with observed experience that in big El Nino or La Nina years the expected effects occur from time to time but not consistently. So I considered the seasonal correlations to be the main criteria in classifying areas, and it is important to remember that season correlations based upon 20-60 data points have some uncertainty. The snowfall data for strong El Nino and La Nina months, added in 2013, has caused me to classify a few more areas as mildly favored by La Nina. These tend to have only mildly negative correlations but snowfall during strong La Nina months exceeds snowfall during strong El Nino months by 15-20%. At most of the strongly favored areas snowfall during strong La Nina months exceeds snowfall during strong El Nino months by 30% or more.
La Nina strongly favors Washington State and inland areas ranging as far north as Revelstoke/Banff in Canada and as far south as Jackson Hole. Oregon and Colorado's farthest north area Steamboat are mildly favored, and there are scattered areas in the Northern Rockies of both U.S. and Canada that are only mildly or minimally affected. I was somewhat surprised that the snowiest Vermont areas (Jay, Smuggler's Notch, Stowe) are mildly favored by La Nina, while most other eastern areas are minimally affected.
The other surprise is that coastal British Columbia is not that sensitive. The exception is Whistler base which had huge snow during the big La Nina years of the early 1970's. It has not done so well during more recent La Ninas due to global warming effects of more rain at its low 2,000 foot elevation. Whistler shows minimal La Nina sensitivity up at 5,000 or 6,000 feet, and the same is true for Mt. Washington on Vancouver Island at 4,000. Note on the El Nino page that the Valdez/Thompson Pass area of Alaska slightly favors El Nino.
Australia/New Zealand have been reputed to be favored by La Nina, but in 2006 I acquired data for 3 South Island New Zealand areas that show little El Nino/La Nina impact. Spencer's Creek (near Thredbo and Perisher Blue ski areas) snowpack data does show that Australia is mildly favored by La Nina.
In La Nina years the favored Northwest and Northern Rockies resorts are generally more likely to be covered by Christmas as well as getting extra snow through the season. November 2007 was not as strong as other La Nina early seasons, but these areas ended up above average for the 2007-08 season as a whole including record snowfall at 5 of them.
In El Nino years my general advice to avoid advance bookings until sufficient snow is on the ground should be taken more seriously at these areas, particularly where average snowfall is modest and there is less margin for error. High snow areas like Jackson, Fernie and Steamboat are probably still just fine during their normally prime months of January and February.
In 2010-11 and 2011-12 we had 2 contrasting La Nina seasons. 2010-11 was the overall best natural snow season in North America in at least 40 years while 2011-12 was the worst in 20 years. However the La Nina favored regions were the ones that escaped drought in 2011-12. The Pacific Northwest and western Canada had strong seasons and the U.S. Northern Rockies were only slightly below average.
I have constructed graphs to illustrate the variability of the snowfall correlations to El Nino/La Nina. The one below is for selected areas favorable to La Nina.
The horizontal axis lists all the past ski seasons since 1966-67 in order of strong El Nino at left to strong La Nina at right. The vertical axis is percent deviation from normal snowfall. The blue line is the sum of MEI indicies from OCT/NOV to APR/MAY, scaled to fit the graph.
For Washington and Oregon I selected the Mt. Rainier (purple line) and Crater Lake (yellow line) National Park data because it was complete since 1966-67. Mt. Rainier is close to Crystal Mt. ski area, and Crater Lake is close to Mt. Bailey snowcat skiing and a couple of hours drive from Mt. Bachelor ski area. Jackson Hole (orange line) and Sunshine Village (light blue line) are good representative ski areas for the Northern Rockies of the U.S. and Canada respectively.
Results are quite consistent for these 4 areas in the strong La Nina seasons. All 4 areas are at least average in the top 8 La Nina years except for Sunshine at 94% in 1974-75. In the 2 highest years 1973-74 and 1970-71, 3 of the 4 selected areas were over 130% of normal snowfall. And in the 5th highest 1998-99, 3 of the 4 areas were over 140%. Average snowfall at all 4 areas over these 8 years is about 125% of normal
At Mt. Rainier, Jackson and Sunshine the top 7 El Nino seasons through 2010 were all below average. Average snowfall at all 3 areas over these 7 years was about 85% of normal, and the worst case was Jackson at 63% in 1986-87. The 2015-16 El Nino broke the mold, with Mt. Rainier at 112% of normal, and there were many other Northwest and western Canadian areas at or above average.
Crater Lake deviated from the expected pattern, with 131% and 113% snowfall in the 2 biggest El Nino years of 1982-83 and 1997-98. Crater Lake was also 130% in the 7th and 8th highest El Ninos of 1992-93 and 1994-95. We should remember that Crater Lake and Mt. Bachelor are in the middle of Oregon, and that Mt. Hood is next to Washington State and favored by La Nina as much as Mt. Rainier.
But the mixed results from Crater Lake should remind us that the "mildly favored" areas listed above will have less consistent El Nino/La Nina impact than the "strongly favored" areas like Mt. Rainier, Jackson and Sunshine.
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