El Niño Poised to Shake Up North American Ski Season
An emerging El Nino weather pattern could bring a winter of contrasts across North American ski resorts this year.
El Nino is a climatic phenomenon that involves the periodic warming of ocean surface temperatures in the equatorial Pacific. It occurs every 2-7 years on average and typically lasts around 12 months, peaking between December and February.
How El Niño works. Credit: NOAA . We are reader supported. We may collect a share of sales from the links on this page. As an Amazon Associate, we earn from qualifying purchases.
90% Chance of Moderate to Strong El-Nino
This winter, forecast models indicate a greater than 90 percent chance of a moderate to strong El Nino event developing by November and persisting through spring 2024. If it continues intensifying as expected, the impending El Nino could have significant implications for snowfall across ski country.
"With the odds heavily favoring El Nino's formation and longevity, we need to brace for the likelihood of an extremely variable ski season in different parts of the continent," said Mark Silverman, editor of Ski Magazine.
During an El Nino winter, the southern branch of the polar jet stream frequently dives southward over the U.S. and Canada, driving Pacific storm systems along a more southerly track. This generally translates to increased moisture and snowfall across the southern Rockies, Utah, California and the Southeastern U.S.
Slammed With Heavy Snow
Meanwhile, the northerly storm track shifts away from the Pacific Northwest and Western Canada, causing warmer and drier conditions across northern ski zones.
"If the jet stream indeed pushes south as expected, ski resorts in Colorado, New Mexico, Arizona and Utah are poised to reap the rewards of enhanced snowfall," said Mike Richardson, meteorologist with OpenSnow.
Specifically, Richardson predicts that resorts like Telluride, Taos and Purgatory in Colorado and Wolf Creek and Red River in New Mexico could see snow totals exceeding 200 inches. Similarly, Utah gems like Snowbird, Powder Mountain and Sundance may also hit the jackpot with above-average powder days.
Farther west, California resorts will likely get slammed with heavy snows off the Pacific Ocean.
"Being the first line of defense against incoming systems, we expect places like Mammoth Mountain, Big Bear and Mount Shasta to exceed their average yearly totals," said Max Dreyer, senior meteorologist with the National Weather Service.
More Ice Across The Sierra Nevada
Meanwhile, icy conditions may plague the slopes of the Sierra Nevada. "Higher freezing levels could create rain-snow transitions in the high country, potentially icing up resorts around Lake Tahoe," cautioned Dreyer.
Out east, southern stalwarts like Cataloochee in North Carolina and Snowshoe in West Virginia could also benefit from the southward jet stream.
Conversely, the altered storm track may shortchange ski zones across the Pacific Northwest, British Columbia and Alberta accustomed to prodigious snowfall.
"Whistler, Sun Peaks, Revelstoke and other B.C. resorts will likely see below-average snow totals and warmer than normal temperatures overall," said Richardson.
Similarly, Washington and Oregon may face shorter seasons with reduced base depths. "Places like Mount Baker, Stevens Pass and Mount Hood need to hope for perfectly-timed cold snaps to supplement the moisture," noted Silverman.
However, forecasters emphasize that each El Nino brings a unique mix of weather patterns, meaning unusual events can transpire. The intense 2015-16 El Nino defied expectations by burying the Pacific Northwest in snow, while leaving California largely high and dry.
"It's critical to remember that no two El Nino events are the same. Subtle factors can conspire to bring snowy surprises anywhere, regardless of the seasonal outlook," stressed Dreyer.
How El Nino Alters Global Weather Patterns
To understand how El Nino may influence upcoming snow patterns, we must examine how it arises in the first place.
El Nino begins as a weakening of the easterly trade winds over the tropical Pacific. This allows a mass of warm water to migrate eastward and accumulate off South America's west coast.
As this warm pool expands, it pumps heat and moisture into the atmosphere, fueling heavy rainfall and storminess in the eastern tropical Pacific.
These local impacts have global repercussions. Rising air and enhanced convection over the central Pacific alters the large-scale atmospheric circulation known as the Walker circulation, which spans the tropics.
Essentially, the rising motion over the central Pacific needs to be counterbalanced by sinking air elsewhere. This typically occurs over the western Pacific and Indian Ocean, disrupting cloud formation and rainfall patterns from Asia to Africa.
Additionally, the areas of altered convection create immense heat sources and sinks, generating waves in the atmosphere akin to the ripples formed when throwing stones into a pond.
These planetary-scale waves, or Rossby waves, transmit the climate impacts globally by changing wind speeds and directions thousands of miles away. Eventually, they propagate upward, distorting the strong winds of the polar jet stream encircling the mid-latitudes.
"By changing the jet stream's speed and direction, these ripples essentially rearrange the atmospheric flow and modify storm tracks across continents," explained Dreyer.
During El Nino, the bulk of tropical heating shifts eastward, tugging the jet stream southward over North America. This puts southern ski zones directly in the storm track while shunting precipitation away from the north.
Forecasting the Impacts of a Strong El Nino
If the brewing El Nino intensifies as forecast models suggest, we're in for a season of skiing extremes across the continent. However, the strength of its anticipated impacts remains uncertain.
Global climate models indicate sea surface temperatures will exceed 1.5 degrees Celsius above average through winter. Such readings qualify as a moderately strong event. Only two such events have occurred in the past 40 years: 1982-83 and 1997-98.
Those winters brought tremendous snowfall along the southwestern U.S. In California,1982-83 still holds the record for the snowiest season at Mammoth Mountain, with over 600 inches accumulation. Meanwhile, Utah's Snowbird received 780 inches of fluff in 1997-98, the resort's snowiest on record.
"If this El Nino attains the magnitude of those historic events, the southern Rockies are in for a season of biblical proportions," said Silverman.
However, meteorologists caution that the intensity of El Nino doesn't correlate directly with the amount of snowfall at specific locations. The strongest events don't necessarily yield the snowiest winters everywhere.
While stronger El Ninos typically enhance the probability of increased precipitation across the southern tier, other weather factors come into play. Not all storms track according to the seasonal climate pattern.
For instance, periodic atmospheric oscillations like the Madden-Julian Oscillation (MJO) can bolster or disrupt the El Nino-influenced jet stream at any moment. The MJO refers to pulses of cloudiness and rainfall propogating eastward around the tropics over 30-60 days, which add an element of variability.
"The MJO can work constructively or destructively with El Nino, complicating forecasts," explained Richardson. "It essentially increases weather noise on shorter time scales."
Furthermore, scientists have found that natural climate cycles like El Nino are exhibiting more irregular behavior as the climate warms. Forecast models are struggling to simulate the intricate jet stream dynamics.
"We know El Nino shifts the odds toward certain snowfall scenarios based on the past. But with an unstable climate, those historical patterns may break down at times," said Dreyer.
For instance, last season's moderate La Nina event was supposed to deliver drier conditions across the Pacific Northwest and increased snowfall to California. Instead, the Northwest enjoyed a bountiful snow year while California remained mired in drought.
"Given the complex physical processes involved, uncertainty will always permeate seasonal forecasts to an extent," stressed Silverman.
Preparing for the Winter Ahead
With meteorologists united on El Nino's likely formation and its broad impacts on winter weather regimes, how should skiers and snowboarders prepare?
Industry experts advise paying close attention to seasonal snowfall projections for your target destinations, but avoiding fixation on specific forecasts.
"The strength of the El Nino provides clues about general trends, like above or below-average snowfall," said Richardson. "But short-term weather events can overwhelm the climate signal at times, so better to focus on probabilities over absolutes."
Instead, maintain flexibility in your plans to capitalize on emerging snow patterns. Consider purchasing multi-resort passes to expand your options, or leave some slack in your itinerary to chase storms as needed.
"Focus on finding the steepest terrain with northern exposure to preserve quality snow regardless of totals," advised Silverman. "Then, let the weather guide you toward powder day by day."
El Nino winters also tend to feature more variable temperatures. To prepare, pack clothes for potential cold snaps but also spring-like conditions on southerly flows.
By adapting to the cards dealt rather than fixating on the pre-season outlook, you can still carve up countless freshest tracks despite El Nino's influence.
"Whether the jet stream locks in or wavers, remember that teams of patrollers and snowmakers are working round the clock so you can enjoy winter safely," reminded Silverman. "The magic of snow remains the magic of snow, no matter how much falls."
One thing is certain --- the atmosphere is about to unleash its winter fury. From Vermont's glades to Whistler's peaks, a season of skiing adventures awaits across North America.
El Nino Snow Predictions
|El Nino Notes
|Southern Rockies (CO, NM, UT, AZ)
|Above average, potentially record snowfall totals over 200 inches
|Colder than normal with good preservation of snowpack
|Increased moisture feeds snowstorms tracking south
|California (Sierra Nevada)
|Well above average snowfall, 400+ inches possible
|Colder with some icing issues possible
|Heavy snow off Pacific, but freezing level fluctuations a concern
|Pacific Northwest, Western Canada
|Below average snowfall due to northward shift in storms
|Warmer than normal, challenging snow preservation
|Drier pattern shortchanges regions accustomed to heavy snow
|Southeastern US (NC, VA)
|Above average snowfall
|Colder than average
|Southward dip in jet stream to benefit southern resorts
|Variable snowfall around average
|High uncertainty based on day-to-day weather