Photo: Arizona Office of Tourism

Got Snow? Effects of Climate Variability, Change on Arizona Skiing

by Joe Gelt

Skiing requires snow; snowfall depends upon atmospheric conditions. Simple and obvious as these statements are they raise a complex question: what effect will climate variability and change have on Arizona’s ski industry? Two University of Arizona researchers, PhD candidate Rosalind Bark-Hodgins and Professor Bonnie Colby, are examining this question.

Information from climate change models show the ski industry to be very vulnerable. According to such models snowpack will decline, snow seasons become more variable and winter temperatures warmer. The effect will be an increased incidence of winter snowpack melt and sublimation loss. An earlier spring snowmelt will occur, with higher elevations required to maintain seasonal snowpack.

This situation does not bode well for attracting new interest to the sport. Skiing novices are more likely to learn at lower elevation “local” ski areas, those most vulnerable to the effects of climate change. These same beginners also are more likely to be discouraged by poor ski conditions and may lose interest.

Snowmaking can reduce a facility’s vulnerability to climate change by increasing snowpack depth, durability and season reliability, but at a high cost. Variable costs of snowmaking in the Southwest are about $923 per acre foot of snow, and it takes about .43 af of water to make 1 af foot of snow.

Arizona ski areas already experience high variability in snowfall and season length. Climate change might account for some of the increased variability, but annual and decadal scale climate oscillations explain much of it. The researchers tested this premise by modeling Arizona’s two major ski areas (Sunrise and Snowbowl) season data as a function of a key oscillation — El Niño Southern Oscillation (ENSO) and also the Pacific Decadal Oscillation modulated ENSO (ENSO-PDO).

The modeling results show that ENSO and ENSO-PDO significantly and positively predicted snow depth at the snowpack telemetry site (SNOTEL) at Mt. Baldy near Sunrise. Climate oscillations also predicted snowfall at Snowbowl located near Flagstaff.

Bark-Hodgins and Colby also found that climate oscillations significantly explain variability in ski season length and visitation. For example, the model predicts that a one unit increase in the intensity of ENSO increases season length by 18 days and visits by 23,653 from the annual average at Snowbowl. The figures increase to 31 days and 41,449 visitors during an ENSO-PDO year.

The researchers note that climate oscillations, although their effects are significant, account for less than a fifth of the variations in season length and visitations. For example, Snowbowl relies entirely on natural snowfall; other factors that explain season length and visits include timing of first snowfall, snow depth, the incidence of warm spells and powder events and general economic conditions.

Bark-Hodgins and Colby also considered snowmaking as an adaptive strategy to climate variability and change. By enabling ski operators to build snowpack in the absence of natural snow, snowmaking improves the consistency of ski seasons, allowing resorts to open for the crucial Thanksgiving holidays, winter break and Rodeo week vacations. Sunrise’s snowmaking capability covers 10 percent of its terrain; Snowbowl has plans for 100 percent snowmaking capacity. Snowbowl management anticipates applying a base of 64 centimeters over the terrain at the season’s start during a ‘wet’ season to ensure good skiing conditions over the Thanksgiving break, one and half times in an ‘average’ season and two times in a ‘dry’ season, equivalent to 427 af, 640 af and 854 af of snow per season, respectively.

Higher temperatures resulting from climate change will increase energy costs and water losses of snowmaking. Snowmaking then may become uneconomical. Further, more warm spells may significantly shorten the ski season, and the costs to replace melted snowpack may become too high.

The models are able to predict the effect climate change will have on the ski industry at Snowbowl and assess the economics of snowmaking. For example, the models predict that a 100 cm snowpack decline at Snowbowl could contract its season 11 days, reduce visits by 7,348 and economic output by $0.91 million. Meanwhile making snow could become more costly; replacing all the snow with manmade snow would increase costs by $0.77 million and water use by 380 af. This leaves little room for snowmaking demands for a resort with an overall water supply of 486 af for snowmaking.

The researchers suggest various non-snowmaking adaptations. Skiing could be limited to top slopes where snow is more reliable. Also resort operators could use ENSO forecasts to determine hiring and marketing, and they could restructure prices to encourage opportunistic skiers.

For additional information contact project researchers: Rosalind H. Bark-Hodgins (rbark@email.arizona.edu), PhD candidate, UA’s Office of Arid Lands Studies or Bonnie Colby (bcolby@ag.arizona.edu), professor, UA Department of Agricultural and Resource Economics.
This research was funded by the National Oceanic and Atmospheric Administration’s Climate Assessment in the Southwest (CLIMAS) grant, Contract No.: NA16GP2578, Variability, Social Vulnerability, and Public Policy in the SW US States: A Proposal for Regional Assessment Activities.

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