Meteorological winter is here. What awaits Utah this season?

SALT LAKE CITY — Despite a warm and dry start to the season, Utah’s statewide snowpack ended the meteorological fall slightly above average at 2.8 inches of snow water equivalent.

However, meteorological fall typically produces appetizers compared to meteorological winter, Utah’s main snowfall. About two-thirds of Utah’s mountain snowpack – a calculation of the water in fallen snow – falls between early December and late February.

That’s according to the 30-year average of Natural Resources Conservation Service data collected from 1991 to 2020. Since approximately 95% of Utah’s water supply comes from snowpack collection and spring runoff, the success of the meteorological winter often determines the entire water year.

“This is the time when we get the most snow, so that’s very significant,” Candice Hasenyager, director of the Utah Division of Water Resources, said of the season, which began Sunday.

A good winter is also important for outdoor snow recreation, but what awaits this winter remains a bit of a mystery as long-term forecasts do not provide a clear signal regarding precipitation. However, this is self-evident when you consider the conditions over the Pacific Ocean.

Utah’s winter outlook

The National Weather Service’s Climate Prediction Center updated its La Niña watch last month and found there was about a 57% chance that the oceanic pattern would occur by the end of this year and last through the first quarter of 2025.

Stronger-than-average trade winds blow the warm waters of the Pacific Ocean westward, allowing cooler waters in the eastern Pacific to resurface during a La Niña pattern, as noted by the National Oceanic and Atmospheric Administration. This typically causes the jet stream to move north during the winter, often forming a track that sends winter storms through Alaska, the Pacific Northwest, and the Upper Midwest as the systems move east.

Meanwhile, warmer and drier conditions generally emerge across the southern United States during a La Niña pattern.

This is also evident in the Prediction Center’s final outlook for the meteorological winter, with most regions in the Upper West and Great Lakes experiencing the highest chances of precipitation this winter. The southwest and southeast have a higher chance of drier conditions.

However, Utah is less affected by La Niña – or El Niño – than other states. Both oceanic patterns tend to help or hurt areas north and south of the Beehive State, while Utah tends to have a wide range of winters that are good, bad, or somewhere in between. It depends on where the jet stream forms.

The last three La Niña winters – 2020-21, 2021-22 and 2022-23 – are perfect examples of this. Utah recorded just 2.34 inches of precipitation statewide in the winter of 2020-21, which was the 18th driest meteorological winter since 1895, according to federal climate data. The following season was also below normal, but closer to normal.

Then, in the winter of 2022-23, Utah reached 5.78 inches statewide – the ninth wettest winter on record. That same water year also produced the state’s largest snowpack on record, amplified by jet steam that drove recurring storms through Utah. It was larger than the 2020-21 and 2021-22 water years combined.

Long-term forecasts for the next three months reflect this uncertainty. Most of Utah is classified as “equal chance,” meaning there is about the same chance that Utah will experience wetter, drier, or near-normal precipitation this winter. Southern Utah has a slightly higher chance of below average precipitation.

Most of the state has a slightly higher chance of temperatures being above normal over the next three months. Only a small portion of northern Utah is given the same temperature probability.

Utah’s Water Savings Account

Hasenyager told KSL.com that she is hopeful, but that the state currently has a saving grace. Utah’s reservoir system was nearly three-quarters full in December, about the same level as this time last year. It is also 20 percentage points above the winter average, following repeated above-average snow amounts and lower consumption averages in recent years.

This increases Utah’s water reserves in case the state suffers another bad season.

“You are our bank account. They help us bridge the periods when the snow cover and runoff are not optimal,” said Hasenyager. “As always, we’re hoping for a big year. But if for some reason we can’t do that, it’s nice to have the reservoir (capacity) available.”

She adds that measures to reduce water use are still recommended in case there is a bad winter followed by further drought in the summer. But another good winter would mean another boost for the Great Salt Lake and Lake Powell, two major bodies of water that remain well below full capacity after sharp declines during the two-decade-long “megadrought.” Both have benefited from controlled releases from reservoirs to address flooding problems.

Gov. Spencer Cox said Monday he believes the Great Salt Lake could even move into “healthy territory” by next spring if the Great Salt Lake Basin has good snowpack again.

“We’re hoping for a good year,” he said. “Regardless of whether we have another great year, a mediocre year or a terrible year, we are in better shape than we have been in many years because of (conservation efforts).”