La Nina could bring relief and extra inches of snow after warm, dry September

Snow begins to fall in August 2022 at Arapahoe Basin Ski Area. September is expected to be warm and dry, but meteorologists are expecting that a La Niña weather pattern could bring an especially snowy winter.
Clay Wright/Courtesy image

Winter sports fanatics are looking toward the late fall and winter to see if a substantial La Nina pattern will fall over Summit County, and current predictions show it not out of the realm of possibility. 

Each month, the National Oceanic and Atmospheric Administration releases a three-month outlook for the entire country. Currently — for the prediction spanning December, January and February — much of the country besides states on the southern border is expected to have a chance at average or above-normal precipitation.

What is La Nina? 

La Nina is an oceanic and atmospheric phenomenon that is the colder counterpart of El Nino. According to the National Ocean Service, during La Nina events, trade winds are even stronger than usual, pushing more warm water toward Asia. Off the west coast of the Americas, upwelling increases, bringing cold, nutrient-rich water to the surface. These cold waters in the Pacific push the jet stream northward.

Episodes of El Nino and La Nina typically last nine to 12 months, but they can sometimes last for years. El Nino and La Nina events occur every two to seven years, on average, but they don’t occur on a regular schedule. Generally, El Nino occurs more frequently than La Nina.

“The effects of La Nina appear to show much of the Western U.S. receiving average to above-average snowfall during these significant events,” Sam Collentine, a meteorologist at OpenSnow, said. “Again, though, the pattern doesn’t hold 100% of the time.”

During a La Nina, what happens in Summit County?

In the National Oceanic and Atmospheric Administration forecast, much of Colorado’s ski country — including Summit County — is expected to have temperatures “leaning above” normal with a 33% to 40% probability. Over the same period of time, precipitation will be expected to have equal chances of being above or below average. 

The 2010-2011 ski season had a similar La Nina pattern to what is currently being predicted, and during that year, Breckenridge received a total of 519 inches of snow from November to April, 180% of the normal amount that the resort usually sees. Loveland Ski Area also saw a substantial amount above normal, with 539.9 inches falling in the same six months. 

“October snowfall was above average, with a widespread storm through the Northwest and much of the Rockies during its last week,” a 2011 season report from reads. “Snow from this storm is included in season totals for many areas as it contributed to the strong early season conditions and to some areas advancing their opening dates. Mid-November snow was abundant in Utah’s Cottonwood Canyons and Front Range Colorado and followed up by a major storm in the Sierra that also pushed into the Rockies.”

In August, the Climate Prediction Center released that it expects that La Nina will continue, with chances for La Nina gradually decreasing from 86% in the coming season to 60% during December to February.

What happens until then?

Monsoonal rains — a summer weather pattern that brings much-needed moisture to most of the state — have ended, according to reports from the National Weather Service in Boulder. Until then, September is expected to be especially warm and dry. Currently, there are still no fire restrictions in the county, but on Sept. 2, Red, White and Blue Fire District increased fire dangers in Summit County from low to moderate — mainly because of warmer temperatures, lower humidity and faster wind speeds. 

For the rest of this week, Summit County temperatures will stay in the 70s mostly, with some highs reaching 80 degrees. Chances of showers or thunderstorms are low, and gusts of wind can be as high as 15 miles per hour until Wednesday evening.

“Moisture looks to be on the scarce side and for now will only be indicating isolated showers for Friday and Saturday,” Entrenkin said. “Forecast soundings indicate strong stability at or near mountain tops, so thunderstorms are not likely on the plains.”

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