How much might it snow in Summit County this winter?
August 22, 2018
Fall is landing in Summit County with chill and raindrops, and focus is starting to shift from the stress of a dry, fiery summer to hopes for a snow-packed winter. While it is far too soon to accurately guess what kind of snow the High Country will wind up getting, there's at least hope for average snow in Summit based on predictions for the 2018-2019 climate pattern.
El Niño is a term originating from the 1600s from the Spanish "El Niño de Navidad," or child of the nativity, as the pattern usually occurs around Christmas time. The importance of the climate pattern, which alternates with a neutral or La Niña pattern every two to seven years, can't be overstated. It can affect the livelihoods of fishermen in Central and South America, cause severe droughts in South Asia, and cause major and minor disruptions to typical climate patterns all over the planet.
El Niño sees a warm pocket of ocean water form in the central and eastern Pacific Ocean, extending from Central and South America outwards.
The opposite pattern, La Niña, causes cold water to collect in that same part of the Pacific.
The type of pattern has downstream effects in the United States, affecting where cool, moist air can wind up by shifting the path the Pacific jet stream takes across the country. The biggest impact of El Niño occurs in the winter from December through February.
El Niño can shift jet streams south, pushing cooler, wetter weather into Colorado's backyard, whereas La Niña usually shifts the jetstream north and brings the opposite — hotter, drier weather — to the western U.S. La Niña was one of the reasons for the drought and wildfires across the west this summer.
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Joel Gratz, owner of OpenSnow.com and known to Summit locals as the resident snow expert during ski season, posted his first look at what kind of climate pattern we might experience in the coming months. Gratz said that the NOAA's Climate Prediction Center is offering a 70 percent chance of a "weak" to "moderate" El Niño. He said that information is important for longer-term forecasts, but still not enough to accurately predict the amount of powder the county will get.
"It's one of the better predictors for the six-month winter forecast, which is why you always hear about it," Gratz said. "It's not because it's the only predictor, but because it's one of the only good predictors we have for a long-term forecast."
Gratz said that the amount of precipitation has a fair correlation with stronger El Niños, with stronger patterns often resulting in big dumps through the winter. However, Gratz said that merely weak or moderate El Niños are not reliable to predict snow.
"I would temper expectations this season," Gratz said. "Whether it's la Niña or El Niño, there isn't a super strong correlation in Colorado. For Summit County, a really really strong El Niño can bring a lot of snow, but these weak to moderate patterns don't present much of a correlation."
Gratz also said that the "dividing line" for patterns can run through Colorado, creating that much more uncertainty for local forecasts. This past winter, La Niña's dividing line between cooler wet air and drier hot air ran straight through Summit County, leaving areas north and east of the county with average precipitation while leaving most of the western slope and southwest bone-dry this winter. Summit was stuck in the middle with less than average snow.
Even in an El Niño year, other factors, such as local temperatures and the exact path of the jet stream that separates the cool and dry air, may be more important than the broader pattern occurring in the Pacific, and even a minor jetstream shift can change local day-to-day weather patterns.
"Even if El Niño was a good predictor, it couldn't get us to such a specific level that we can predict how much snow we'll be getting," Gratz said. "For snow lovers and meteorologists, long-range forecasting based on El Niño is more of a fun exercise than a useful exercise."
Gratz said that closely following short-term forecasts is the way to go during ski season. To help people get those short-term forecasts at the palm of their hands, OpenSnow has launched an app called OpenSummit that tracks weather conditions for mountain peaks in Summit and many others across the country. The app is available on the Apple app store, with plans to expand to Android next summer.