It’s been said that it’s nearly impossible to predict the weather, but one local forecaster is close to reality when he called snowfall totals for this season back in October.
Cory Gates and his business partner, Ryan Boudreau, started aspenweather.net in 2011 to provide “micro forecasting” specifically for the Aspen area. Gates, who worked for nearly two decades for the National Weather Service, began his analysis of weather data late last summer to predict snowfall for the 2012-13 season.
From October to May, Gates predicted 280 inches at Snowmass, 258 inches at Aspen Mountain and 269 inches at Aspen Highlands. Comparing that to Aspen Skiing Co. snowfall data, Gates claims he is within inches of his predictions.
According to daily snow reports, SkiCo spokesman Jeff Hanle said Snowmass received 235 inches from November to closing day last Sunday and 207 inches at Ajax. Hanle said Snowmass received 15 inches in October; he didn’t have data for that month at the other ski areas.
Highlands, which is still open, has received 202 inches from November through Friday, Hanle said.
While SkiCo has stopped collecting snowfall totals at Ajax and Snowmass because they are closed, the ski areas have accumulated at least 32 inches since last weekend, Gates said, adding that up to 6 more are expected through Monday.
“I think I will be within an inch, which is mind-boggling,” he said of his October through May prediction.
Gates was off on his forecast last year, which was shrouded in drought conditions and proved to be an anomaly in weather patterns.
He starts looking at the state of the atmosphere in late August, analyzing the water temperatures in the equatorial Pacific Ocean and the pressure differences between land masses. That typically will determine whether it will be a La Niña or El Niño year. Models last fall indicated that this season would be neutral year, based on water temperatures.
“I predicted 20 percent below” average snowfall for area ski resorts, Gates said.
The SkiCo claims on its trail maps that annual snowfall for Aspen/Snowmass ski areas is 300 inches annually. However, Hanle said that number has been discussed recently among SkiCo officials.
The discussion centers around how many years back SkiCo should be going to use average snowfall, especially in light of climate change, which presents many unknown variables in weather patterns.
“We don’t know if [climate change] changes snowfall but it does change patterns,” Hanle said.
Gates works informally with on-mountain SkiCo crews that collect weather data and snowfall in the middle of the night to correlate his reports on the website.
At various locations on the mountains, SkiCo has what are called “snow plots” that collect information for snow safety personnel and snowfall data for the public.
The automated weather stations incorporate sonar technology to gauge atmospheric conditions like wind speed and direction, temperature, barometric pressure and humidity.
The snow plots also measure snowfall by the hour, 24 hours a day. A board that collects snow flips every day at 9 a.m., which is the basis for SkiCo’s daily snow reports.
As for next season, Gates is relying on statistics for an early prediction: Based on snowfall data from the city of Aspen’s water plant, there has only been one instance since 1934 in which there were three years in a row that had below-normal precipitation — from 1952 to 1955.
“It’s not probable that will happen again,” Gates said. “Next year will be normal or above.”
Gates claims that for the past eight years, his predictions have been within a foot or two. In the epic snow year of the 2007-08 season, Gates predicted 545 inches; SkiCo reported 560 inches.
Local skiers and snowboarders have come to rely on Gates and Boudreau’s valley-specific weather reports in both the Aspen Daily News and a more detailed one on their website, which can only be accessed by membership. Annual memberships cost $60, or $40 for six months. Gates said he and Boudreau have 600 members on the website, which also forecasts summer weather patterns.
“[Gates] is certainly very good at what he does,” Hanle said, adding he’s relied on aspenweather.net on some powder days when other meteorologists have gotten it wrong. “He’s providing a micro-targeted forecast, which is what is wanted and desired by powder skiers and businesses in the valley.
“It’s his passion, and it shows.”