A winter wonderland has a lot of moving parts.
Start with the relative warmth of the Pacific Ocean near the equator. Throw in a wobbly jet stream or two, the vagaries of mountain ranges and an intractable drought.
What could possibly go wrong?
Only everything. When Southern California ski resorts look ahead to this winter, they can't help but recall last year, when an otherwise generous El Niño didn't send its gifts far enough south.
Five hours north of L.A., Mammoth received 400 inches of snow last season, more than twice the total of the year before. By comparison, 99 inches fell on Snow Summit last season in nearby Big Bear.
It turns out that rain and snow are possible to predict, but forecasting where it all lands can be as errant as a shanked punt.
"SoCal is probably staying dry this coming winter,"" said Bill Patzert, an oceanographer with the Jet Propulsion Laboratory in La Cañada Flintridge. "But Northern California and Mammoth could get some nice snowpack, much like last winter.
"The question is will those North Pacific storms give us a direct hit or a glancing blow?"
Last season's El Niño came to an end in June, putting forecasters on watch for La Niña. Las Niñas typically follow Los Niños and push jet streams north, keeping Southern California even drier than usual.
“I often call La Niña the ‘Diva of
"It's been so weak that it may open the door a crack for those storms to come down," he said.
The weather expert acknowledged that nothing is certain in long-range forecasting and that a Pineapple Express — a corridor of atmospheric water that sometimes roils up from Hawaii — could always turn things around.
Still, the outlook for the half a dozen or so resorts ringing Los Angeles is not good. In fact, the resorts are coming off the five driest consecutive years since recordkeeping began in the 1870s.
"Anyone who sells off their 401(k) and bets on a wet winter, I would call that foolish to reckless," Patzert said.
Paul Bauer, chief operating officer of Southern California's Mountain High resort, has learned to expect the unexpected. He's tracking ski weather since 1982 and has seen predictions of dry winters turn into wet and snowy seasons, and vice versa.
"Weather is unpredictable," he said. "It's not a perfect science, but there's some science to it."
At Mountain High, 90 minutes from Los Angeles, weather can flip in the middle of the night, confounding snowmaking operations on which the popular resort heavily relies.
In fact, weather science is so fickle, so beyond the comprehension of all the buoys, satellites and computer modeling that are used, that even an operation as reliant on snow as the Sierra's Mammoth Mountain barely bothers with them.
"Long-term predictions are just such an inexact science that we don't get any kind of actionable information from them," said Tim LeRoy, a spokesman for Mammoth.
Like Mammoth and Mountain High, Deer Valley Resort in Park City, Utah, concentrates more on short-term forecasts than full-season predictions.
"We really focus on reporting real conditions and what storms produce rather than predictions," a spokesman said.
Most Western resorts subscribe to national weather-predicting services for their forecasts. But in the Pacific Northwest, home to a veritable car wash of winter conditions, Canada's Whistler Blackcomb relies on in-house experts to forecast what's ahead for the week and how to staff daily operations.
Whistler Blackcomb also takes an enlightened approach to providing accurate and timely snow information, relying on third parties for forecasts to avoid any potential bias in an industry that generally has a reputation for amplifying snow depths and forecasts as a way to lure skiers.
The Whistler Blackcomb weather team also includes two avalanche experts.
"We dig profiles, and we look at the layers physically," said Anton Horvath, who has spent 20 years in forecasting at Whistler Mountain, north of Vancouver in British Columiba.
"We analyze snowpack throughout the season," he said. Among the concerns, he explained, is the slippery slope of new snow, old snow, wet and dry snow, in various depths and textures.
Predicting when all that snow will arrive is another matter.
Like Mammoth and many other Western resorts, Whistler Blackcomb is coming off a triumphant season, and Horvath thinks La Niña might still be strong enough to bring below-average temperatures, which would help maintain snow depths. But who knows?
"I don't put too much faith into any long-range forecast," he says. "There are just too many factors here in the Pacific Northwest."