BOULDER, Colo., Dec. 3 (UPI) -- The hard-pressed American ski resort industry could be facing a serious problem in coming years if European researchers are correct: less snow because of global climate change.
At a conference on sport and environment this week in Turin, Italy, University of Zurich tourism expert Rolf Burki and colleagues predicted the amount of snow falling at low-elevation European ski areas will become increasingly unpredictable and unreliable over the coming decades, because of global warming.
Burki also said ski resorts in North America and Australia will be affected.
New research indicates that, under the worst-case scenario, none of Australia's ski resorts will be economically viable by the year 2070, he said.
In Switzerland, an estimated 15 percent of ski resorts already are enduring unreliable levels of snowfall. This figure could increase to between 37 percent and 56 percent in the coming decades. Impacts could be even more severe in Germany and Austria. The study considered low elevation to be about 1,300 meters, or about 4,200 feet above sea level.
The Swiss study did not look in detail at North American, although it did say that resorts may have to increase artificial snowmaking by 48 to 187 percent by 2070.
Though no comparable research has yet been conducted for the United States, Mike Dettinger, a research hydrologist for the U.S. Geological Survey in California told United Press International his group has "worked on changes in snowmelt-based stream flows across western North America, as well as simulations and projections of how the snowpacks could fare under global warming."
In California, Dettinger said, the snow line in this century could retreat between 1000 and 1500 meters higher than it currently is, although the volume of snow above snowline probably would remain adequate for human water requirements. "The snowpack story hasn't been entirely sorted out yet," he added.
Indications from the Oak Ridge National Laboratory in Tennessee are not encouraging either. This week, apropos anticipating a white Christmas, the laboratory reported fewer snowfalls are becoming the norm between Thanksgiving and Christmas Eve.
"Looking at states that typically get snow, 187 of 260 weather stations have reported fewer days with snowfall since 1948," said Oak Ridge meteorologist Dale Kaiser. The decrease in snow days has been especially pronounced east of the Mississippi River, he said, which is where most of America's low-elevation ski areas are located. The trend toward fewer snow days has been most pronounced in the Northeast, but many weather stations in the West showed increases in snow.
"Although this work shows real changes over parts of the United States in snowfall days and temperature for this 30-day period," Kaiser explained, "this cannot be used to draw conclusions about changes in weather over the entire winter, nor do these findings necessarily relate to the broader issue of global warming."
According to the U.S. National Ski Areas Association in Lakewood, Colo., skier days, as they are called, have been fairly stable since the mid-1980s, hovering a little above or below 52-million per ski season. Lift ticket prices, however, have doubled during that period.
The snowpack issue has important implications beyond the ski industry. In the West, much of the summer and fall water supplies come from melting snowpack.
"Historically, over the last 40 or 50 years, there has been a pronounced trend toward having the snow melt earlier in the year in rivers from New Mexico to Alaska," Dettinger said. "And a general summary would be that what we're seeing is a change in this streamflow timing from a week to two weeks earlier than it did in the middle of the 20th century."
These changes in streamflow timing appear to be connected to a general warming of winters and springs over that time period, he said. "They are in general agreement with changes in when plants get green, and at least some changes in snow packs."
In the long-term, Dettinger said, the result may be more severe, winter flooding in West Coast rivers, which is the season in which most lives are lost and property damage incurred from flooding.
Dan Whipple covers the environment for UPI Science News. E-mail email@example.com