Snowfall is below average this season, but expert says La Niña could turn things around | VailDaily.com
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Snowfall is below average this season, but expert says La Niña could turn things around

A skier and snowboarder ride a chairlift at Arapahoe Basin Ski Area on Dec. 7.
Photo by Ian Zinner / Arapahoe Basin Ski Area

Summit County and Colorado are experiencing below average snowfall early this season, but La Niña could help.

At a Colorado River District webinar Wednesday, Dec. 16, Open Snow founding meteorologist Joel Gratz said Colorado snowpack is about 25% below average. He said Colorado is about two weeks behind its average snowpack level for this time of year but that things could quickly turn around.

“If we get into a good pattern, and it snows every other day or so, we can quickly make up the deficit that we currently have,” Gratz said during the webinar.



The National Oceanic and Atmospheric Administration issued a La Niña advisory Dec. 10, which signifies below average sea surface temperatures in parts of the Pacific Ocean. The colder temperatures can lead to snow, which is why La Niña is generally a good thing for the mountains, Gratz said.

“La Niña does not technically mean that the storms will track a certain way,” Gratz said. “All La Niña means is that the water temperatures in the central Pacific Ocean are colder than average. However, those colder-than-average water temperatures often translate into the atmosphere having a certain set of storm tracks throughout the winter.”



When looking back at the past 100 years, Gratz said La Niña years that are similar to this year’s pattern show areas of above average precipitation. Gratz noted that there isn’t a strong historical correlation between La Niña or El Niño and snow across Colorado, but it appears that the stronger the La Niña, the better the chances of average or above average snowfall.

“The outlook for this season with a moderate-to-strong La Niña is that we should, all things being equal, line up with near average or even above average snowpack across the state,” Gratz said.

Each season’s maximum snow-water equivalent, or the amount of water held in the snowpack, is charted in relation to La Niña winters in blue and El Niño winters in pink.
Graphic from Open Snow

The 10-day forecast for Colorado includes a storm tracking west to east Thursday night into Friday that will bring 3-6 inches of snow. But the week leading up to Christmas doesn’t show good chances for precipitation in the state, Gratz said. He noted that the long-term, two-week forecast shows a colder, snowier pattern around the new year.

Climate also was discussed during the webinar, with Colorado River District Community Affairs Director Jim Pokrandt pointing out that much of the Colorado River basin is enveloped in extreme or exceptional drought, which are the two highest rates of intensity in the U.S. Drought Monitor scale. The drought is making for dry soil, which will mean runoff in the spring is less effective as water seeps into the soil.

Gratz described a similar phenomenon after the average 2019-20 snow season came to a warm end with a faster-than-usual melt out and below average runoff.

Summit County’s temperature increased by 1.9 degrees Fahrenheit between 1895 and 2018.
Graphic from The Washington Post

According to a graphic Pokrandt shared from The Washington Post, Summit County’s temperature increased by 1.9 degrees Fahrenheit between 1895 and 2018. He added that for every one degree Fahrenheit rise in temperature, streamflow is reduced between 3% and 5.2%.

While temperatures have risen, average snowpack has largely stayed the same, Gratz said.

Climate change has contributed to rising temperatures, but Colorado’s snowpack doesn’t appear to be imapcted.
Graphic by Weather5280

Arapahoe Basin Chief Operating Officer Alan Henceroth also joined the webinar, describing the impact of snowfall on the recreational economy.

He said the impact of fresh snow is “almost automatic,” with people visiting ski areas when it snows, helping ski areas generate revenue in the form of lift tickets, restaurant sales and retail operations.

“If we get 6 inches of snow on a Thursday, we can guarantee the next day is going to be good, and Saturday is going to be huge,” Henceroth said.

Henceroth added in an interview with the Summit Daily News that there can be a significant difference in economic impact of an above average snow year compared to a below average snow year.


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