Coloradans look to Super El Niño for major winter moisture

After months of dry conditions and growing concerns about Colorado's water supply, the upcoming winter could bring an opportunity for relief. A developing climate pattern known as a Super El Niño could improve the odds of a wetter season, potentially bringing much-needed snow to parts of the state.

But could it be enough to turn around Colorado's drought?

Peter Goble, assistant state climatologist, said it's possible, but there are no guarantees.

El Niño occurs when sea surface temperatures in the central and eastern Pacific Ocean become warmer than normal. A Super El Niño is an especially strong event, defined by ocean temperatures at least 2 degrees Celsius, or about 3.6 degrees Fahrenheit, above average in a specific region of the Pacific.

While the name sounds dramatic, Goble said there is nothing magical about crossing that temperature threshold. The stronger ocean warming can, however, increase the potential for more pronounced effects on weather patterns.

El Niño weakens the tropical trade winds, influencing the jet stream — the high-altitude river of air that helps steer storms, fronts, and areas of high and low pressure across the country.

During El Niño, the jet stream more frequently splits into two branches. The southern branch can become more active across the southern United States and, at times, southern Colorado. That shift can create opportunities for additional precipitation, although the impacts vary by location and season.

Colorado's drought-stricken landscape needs more than a few passing storms to recover. A strong snow season could make a meaningful difference, particularly if the snowpack melts gradually and sends water into rivers and reservoirs.

Goble said El Niño years tend to favor wetter conditions during the shoulder seasons, especially fall and spring. The connection is less consistent during winter when Colorado's high-country snowpack is especially important.

The outlook also varies across the state. "It's less of a guarantee in winter and so when it comes to our peak season high country snowpack it's a little bit less clear," Goble said.

According to Goble the potential for beneficial snowfall is generally stronger in the San Juan Mountains of southwestern Colorado. That signal tends to weaken farther north, making it harder to predict how much of the state could benefit.

Even so, one especially snowy year could provide substantial drought relief. "One really good snow year can refill our reservoirs," Goble said, pointing to 2019 and 2023 as examples.

Those years demonstrated how a strong snow season can help replenish Colorado's water supplies.

Even with a Super El Niño, Colorado's winter weather will depend on how storms track across the region and where precipitation ultimately falls. Goble compared the potential benefits to playing a game of poker with better cards in the deck. "You have a better probability of drawing a really good hand, but you could still draw a really crummy hand," he said.

In other words, a Super El Niño could improve the odds of a wetter season without guaranteeing above-average snowfall or widespread drought relief.

The distinction matters because Colorado's water supply depends heavily on mountain snowpack. Additional precipitation in one part of the state does not necessarily translate into meaningful gains for every river basin or reservoir.

If the upcoming winter fails to deliver a banner snow season, recovering from the drought could take longer.

Goble said Colorado may need several years of near-average snowfall, combined with careful water management, to make meaningful progress.

Another dry year could make the situation more difficult, particularly because reservoirs entered this season in worse shape than they were before the previous winter's snowpack.

That leaves Colorado facing two very different possibilities: a strong snow season that helps replenish water supplies, or another year that adds pressure to already strained resources.

For now, a Super El Niño offers a reason for cautious optimism — not a promise of a drought-busting winter.