La Niña expected to impact snowfall for the 3rd consecutive winter

Snowmaking at Park City Mountain Resort. Photo: Vail Resorts

PARK CITY, Utah – The National Oceanic and Atmospheric Administration (NOAA) is predicting that Utah’s Winter forecast to be warm and dry due to a third consecutive year of La Niña conditions in the Pacific Ocean.

One of the major factors influencing weather in the United States and other countries, particularly in the late fall, winter, and early spring, is the La Niña climatic pattern, a natural cycle characterized by cooler-than-average ocean water in the central Pacific Ocean.

In contrast to the more well-known El Niño occurs when the Pacific Ocean’s water temperature rises above average, La Niña means “little girl” in Spanish, whereas El Niño means “small boy” or “Christ child.”

Trade winds are even stronger than usual during La Niña, bringing more warm water into Asia. Upwelling increases off the west coast of the Americas, sending cold, nutrient-rich water to the surface. The jet stream is forced northward by the cold seas in the Pacific, which has an impact on weather patterns both domestically and internationally.

Since the colder waters force the jet stream north, a normal La Niña winter in the United States delivers cold and snow to the Northwest and particularly dry conditions to the majority of the southern part of the country and including Utah. Although every La Niña winter is unique, they often favor below-average snowfall in the Southwest of the United States. For Colorado, Utah, and Lake Tahoe, there are only sporadic relationships between snowfall and La Niña winters.

While La Niña is expected to bring a warm and dry winter season, winter forecasts are inherently uncertain since so many factors in the atmosphere are not predictable months or even weeks in advance. Climate change is also adding to seasonal outlooks’ complexity.

Sometimes, La Niña winters can be snowier than average across nearly the entire Western United States, with recent examples including ‘07-08, ‘10-11, and to some extent ‘16-17. However, the past two winters (which were both La Niñas) were low for snowfall across most of the West.

According to OntheSnow, a historical snowfall database, Park City Resort received  404″ total inches of snowfall throughout the 2016-17 season, which was the most in the past 10 years. 2016-2017 was a La Niña year, so there is reason for optimism that she will finally deliver a good snow year to us this year.