John Pomeroy had long sensed something was amiss with the Earth's climate, but a balmy mid-winter rain shower in the Rockies finally offered him incontrovertible proof that dramatic changes were occurring.
It was 2005, and Prof. Pomeroy, one of Canada's leading hydrologists, was re-establishing the Marmot Creek Research Basin that had been shut down in 1986 to make way for the development of the nearby Nakiska ski area in the lead-up to the Calgary Olympics.
"I was setting up a weather station there in January and it was 12 C and raining," Prof. Pomeroy said. "I thought, 'this is bizarre,' and the lower elevations didn't develop a snowpack that winter. When I started comparing our recent data to what they collected in the sixties and seventies and 1980s, the snowpacks at the lower elevations had dropped by half over that period of time."
Over the past 50 years, throughout most of Alberta and British Columbia's mountains, the average nightly low temperature in the middle of winter has increased at least 2 C near the coast and up to 5 C in parts of the Rockies, according to Prof. Pomeroy, a Canada Research Chair in water resources and climate change. That has shortened the spring ski season anywhere from four to six weeks at many hills, he said.
"It's going to be the edge seasons – the fall and the spring – and the lower elevations and the sites that were already marginal that will be first affected [by climate change]," Prof. Pomeroy said. "The ski areas I've seen that are already in trouble … are the ones that are already adapting to it – they're really good at snow making."
However, resorts in the Rockies are much higher and colder than their competitors further west and seem better poised to keep delivering reliable snow to skiers.
Sunshine Village, Lake Louise and Nakiska are all experiencing snow levels in the lowest 25th percentile this season, but the snowfall isn't expected to change dramatically at those places during the peak winter months of December, January and February, Prof. Pomeroy said.
Their terrain is already so cold that, even with "a lot of warming in the middle of winter," operators will be able to weather periods of low precipitation by producing man-made snow, he added.
"The only trend you see at higher elevations is for slightly more late-winter and spring precipitation," he said. "It's still falling as snow mostly, but with continued warming that will shift to rain."
The Rockies could also get more "fairly warm and fairly dry" ski seasons if the El Nino pattern – and the chinooks it brings – continues stretching over consecutive years, which seems to be part of a global trend where weather systems are "stalling" for longer periods of time, Dr. Pomeroy said.
Nakiska, which borders Dr. Pomeroy's research site, has had a strong ski season so far because it is one of the few resorts where chinooks can bring 15 to 40 centimetres of snow in a matter of hours, according to Matt Mosteller, a senior vice-president of marketing at parent company Resorts of the Canadian Rockies. Even without such "big dumps," Nakiska can survive due to its fleet of snow-making guns, he said. Mr. Mosteller said his company hasn't been shown "the clear facts" about how climate change will affect the region in the future, but he is not that worried considering "what we've seen in the last 10 years: the last five have had record or near-record snowfall for us."
"Some would call it luck and some would look at it as a smart business decision as to what resorts we put in our portfolio and their geographic location," said Mr. Mosteller, whose company runs five other areas in the region.
This year, B.C.'s South Coast has gotten a glimpse of warm and wet ski seasons that experts say could be the norm in 35 years if worst-case emissions scenarios hold true. This season, a moderate El Nino system has soaked skiers and kept snowpacks so low that several mountains have temporarily closed or shut down completely. David Lynn, president and CEO of the Canada West Ski Areas Association (CWSAA), representing 135 ski areas and 153 industry suppliers, said that in the short term, warmer and wetter winters near B.C.'s coast could pull powder-hungry tourists further east to ski areas in the Okanagan and the Rockies, but the loss of low-lying resorts in the region will eventually hurt the viability of the entire industry.
"If we lose significant numbers of resorts, particularly concentrated near large urban centres, that's bad for the sport," Mr. Lynn said.
He said that is already happening in California, where ski hills "hammered in recent years" by a prolonged drought have seen skier visits drop dramatically, while Colorado's resorts had a record year last season.
Mr. Lynn said each resort is tackling the problem in its own way and pointed to Whistler Blackcomb's hydroelectric dam as a leading example of the ways resorts are lowering greenhouse-gas emissions. Operators are adapting to global warming by carving out slopes at higher elevations, improving grooming, using glacier blankets to stop summer snow loss. They are also diversifying into summer businesses by offering activities such as ziplines, alpine hiking, gondola rides and mountain biking.
Michael Pidwirny, who teaches physical geography at the University of British Columbia's Okanagan campus, was asked to present his research at the CWSAA's annual conference in April. His research uses data from UBC Forestry's ClimateBC program to calculate the historic snowfall at Western Canada's ski resorts and predict how they would be affected by a warmer climate, as modelled on various global emissions scenarios. He hopes to get funding to establish permanent weather stations at ski hills across B.C. and Alberta to validate what his models are forecasting.
"Two years ago was a good snow year – if things are good, why worry?" he said. "My guess is that this year will be one of the worst years in the history of skiing at B.C.'s coastal resorts. I'm trying to explain to them how knowing about the future is important for decision making."
Meanwhile, Dr. Pomeroy said ski culture has always set fashion and lifestyle trends, and mountains could help drive societal change through educating influential patrons.
"That's sometimes the only place they see nature right up in their face, so [ski resorts] have a great role in educating the public," he said. "The research helps us better understand our water supply and our management system and better manage what snow is left. My hope is still that humanity will figure out alternatives as to how we create energy and reduce our impact, but right now we're headed down a disastrous path."