OpenSnow’s Joel Gratz explains why long-range forecasting is like predicting the Super Bowl
In addition to snow forecasts throughout the winter, OpenSnow has a summer app called OpenSummit that includes weather forecasts for close to 1,000 of the tallest or most notable hiking areas throughout Colorado and the country.
For ski reports, forecasts and predictions, visit http://www.opensnow.com.
How much might it snow in Vail this winter? No one really knows for sure, especially not this time of year.
As a local snowboarder with more than 700 days on the mountain in seven seasons, I only trust two resources when it comes to snow forecasts — my window and Joel Gratz, of OpenSnow.
Gratz and OpenSnow recently released their “long, long-range forecast” for parts of Colorado, but does it really matter?
“The thing is with these seasonal forecasts, most people just want to have a clue about what might happen,” Gratz said in August. “The seasonal forecasts are fun to talk about, but you have to keep in mind what’s predictable and what’s not.”
Locals such as Scott French, who’s been busy expanding his Mountain Gopher grocery delivery service this summer and creating a “Sober & Stoked” documentary, love talking winter this far out, albeit with hesitations for forecasts.
“I don’t put too much effort into it because generally it’s a very vague overlook,” French said of long-range forecasts. “We do have six months of winter, so we’re pretty much guaranteed to have snow. And we’re pretty much guaranteed to have cycles.”
Gratz likens snow forecasts this time of year to predicting who’s going to be in the Super Bowl at the start of the NFL season.
“It’s pretty fun to do the exercise and look at who’s on what team, who could really shine and what rookies could come through, but nobody really knows what’s going to happen,” he said. “One day we might be able to get this right, but it’s not today and it’s not tomorrow.”
What is reliable, Gratz said, is shorter-term forecasts.
“There’s rarely a storm now within sevenish days that occurs without knowing that the storm could occur,” Gratz said. “It could be much stronger or weaker and drop more snow or less snow, but you generally know within sevenish days or so that a storm is coming.”
HOW IT WORKS
Long-range forecasts this time of year focus on water temperatures across the globe, finding a weather pattern in the past 50 years that is similar and then looking back at the past years to see what happened in the ensuing winters.
Are they reliable this far out?
“Not really,” Gratz said.
However, weather patterns this time of year fall under very strong, strong, moderate or weak grouping. Gratz said very strong patterns are very reliable, but once they drop to strong and lower, they’re not as reliable.
In the past 68 years, there have been three very strong El Nino patterns and seven strong La Ninas — 10 strong or very strong patterns in the past 68 years equates to less than one strong or very strong pattern every 10 years. The last very strong El Nino was the winter of 2015-16.
“The rest of the time, you’re kind of scrapping,” Gratz said.
Weather patterns are “tricky” to predict, Gratz said, and there’s much more to it than simply the water temperatures in the ocean and El Ninos or La Ninas, such as jet streams.
However, a common misconception is that there are independent variables related to weather patterns.
“The jet stream is not a driver of weather, it is the weather,” Gratz said.
When forecasters talk about El Nino and La Nina, they are also talking about what those mean to changing the jet stream and the moisture.
Back to the NFL analogy
“A quarterback could have a great game or a bad game, but that often goes with the rest of the team, too,” he said. “If the quarterback is amazing, then the offensive line is probably good, too, and the running back is probably playing well, as well as the defense.
“When we talk about water temperatures effecting storm tracks, that’s what we’re talking about: El Nino effecting the jet stream and all of the things around it which bring us snow or doesn’t bring us snow.”
And when it comes to forecasting Colorado, the dividing line for weather patterns can run right through the state.
Last season, eastern parts of Summit County (Loveland, Arapahoe Basin, Keystone) had pretty normal snowfalls, Gratz said, while the western part of the county (Copper, Breckenridge) was below average.
“You can see that variation within one county just in one year, and that’s hard to predict even a couple weeks out, let alone months,” he said.
For skiers and snowboarders such as French, it’s just nice to be talking snow again.
“I’m stoked on the season. I’m always excited,” French said. “I just hope we get colder temperatures than the previous year. I always think that if things aren’t lining up our way, then we’ll go out and wash our cars or something.”
French’s tactics might be just as reliable as these long, long-range forecasts.
Assistant editor Ross Leonhart can be reached at 970-478-2984 and firstname.lastname@example.org. Follow him on Instagram at colorado_livin_on_the_hill.