The 2022-2023 winter season was remarkable for Aspen Snowmass across all metrics. The snowpack at every mountain trended above normal from December through April thanks to cold temperatures and consistent storms.

As we look ahead to the 2023-2024 winter season, it's important to remember that any winter outlook will contain an inherent degree of uncertainty. However, there are a few clues that we can keep an eye on thanks to everyone's favorite weather phenomenon: El Niño.

For the upcoming winter season, an El Niño looks to be in store, and better yet, current sea surface temperatures are showing a strengthening El Niño event.

El Niño, Explained

The term El Niño refers to the large-scale ocean-atmosphere climate phenomenon linked to periodic warming in sea-surface temperatures across the central and east-central equatorial Pacific.

El Niño represents the warm phase of the ENSO cycle and means that the ocean water temperatures are warmer than average.

Ski Season Snowfall vs. El Niño

The map below shows winter snowfall during seven significant El Niño episodes across the United States. The higher the number, the stronger the El Niño. The blue dots are above average, the white dots are average, and the orange dots are below average snowfall.

The relationship tends to be a mixed bag for El Niño and snowfall in Colorado with most of the state close to average precip and temps during the winter months.

Historical El Niño Seasons @ City of Aspen

After looking back at the seven most recent significant El Niño years and comparing them against the 30-year median snowfall of 166 inches for the City of Aspen, I've found that the median snowfall in Aspen during those El Niño years is 158 inches or 95% compared to the 30-year normal.

• 1991-2020: 158" (30-year normal)
• 1982-1983: 216"
• 1986-1987: 135"
• 1991-1992: 133"
• 1997-1998: 188"
• 2002-2003: 157"
• 2009-2010: 174"
• 2015-2016: 176"

Four out of the seven El Niño years produced above-normal snowfall for Aspen.

For timing, when looking at those seven most recent significant El Niño episodes and comparing them against the 30-year median snowfall for the City of Aspen...

• October: 13" (147%)
• November: 23" (93%)
• December: 16" (64%)
• January: 19" (65%)
• February: 32" (118%)
• March: 31" (117%)
• April: 25" (112%)

There's no clear signal but it tends to be that the shoulder seasons are near or above normal, while the winter months are near or slightly below normal.

Historical El Niño Seasons @ Independence Pass

After looking back at the seven most recent significant El Niño years and comparing them against the 30-year median snow water equivalent (SWE) on March 31 of 15.8 inches at the Independence Pass SNOTEL station near Aspen, I've found that the median SWE near Aspen during those El Niño years is 15.8 inches on March 31 or 100% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 15.8" (30-year normal)
• 1982-1983: 16.6"
• 1986-1987: 15.8"
• 1991-1992: 14.0"
• 1997-1998: 14.9"
• 2002-2003: 16.2"
• 2009-2010: 15.8"
• 2015-2016: 15.0"

Two out of the seven El Niño years produced above-normal snow water equivalent (SWE) near Aspen on March 31 but the trend is very close to normal.

For timing, when looking at the change in SWE each month during the seven most recent significant El Niño episodes and comparing them against the 30-year median change in SWE for that month...

• October: 1.5" (136%)
• November: 3.6" (109%)
• December: 2.1" (75%)
• January: 1.8" (64%)
• February: 2.5" (83%)
• March: 3.5" (125%)
• April: -0.3" (150%)

It tends to be that the shoulder seasons are above normal, while the winter months are below normal.

2015-2016 El Niño Season

The most recent El Niño in 2015-16 produced normal snowfall at Aspen Highlands, normal snowfall at Aspen Mountain, and slightly below normal snowfall at Snowmass.

• Aspen Highlands: 254" (101%)
• Aspen Mountain: 250" (100%)
• Snowmass: 279" (93%)

Overall, history tells us that Aspen Snowmass tends to be right around normal for snowfall during El Niño events, with the potential for a stronger start and end to the season.

Having said all of this, for skiers and snowboarders, keep in mind that when it comes to finding the best conditions, it’s all about timing. To have the best chance of enjoying the deepest powder, our recommendation is to book a trip 7-10 days in advance.

Sometimes, longer-range forecasts can identify possible storms 1-2 weeks (or longer) in advance, but often, forecast confidence in the details of each storm only begins to increase when the system is about one week away or closer.

If you're ready to level up your weather app for the upcoming winter season, consider upgrading to OpenSnow All-Access. Whether you’re chasing powder, searching for sunny days, or something in between, our 10-day snow forecasts, expert "Daily Snow" forecasters, and high-resolution weather maps have you covered.

But don't just take my word for it ... "Any weather app can give a mediocre forecast for a mountain town, but only OpenSnow provides a good idea of actual mountain conditions. It's a small price to pay ($29.99/year) for the best weather forecasts." – Real App Review

Sam Collentine
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