The 2022-2023 winter was a solid ski season for Oregon. The snowpack started above normal for many areas, with a dip to normal mid season, and a shot back to above normal at the end of the season. The late season snowpack in March and April was especially impressive as spring storms brought consistent snow.

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, especially this season with the upcoming El Niño.

Following the third La Niña in a row, sea-surface temperatures are warming with a strengthening El Niño event for the upcoming winter season.

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.

 

In general, El Niño winters tend to favor near normal to below normal snowfall in Oregon with the exception being southern Oregon along the California border. There is also some indication that a stronger El Niño favors closer to normal and even above normal snowfall.

Historical El Niño Seasons @ Mount Hood Resorts

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 52.3 inches at the Mt Hood Test Site SNOTEL on Mt Hood. I've found that the median SWE on Mt Hood during those El Niño years is 50.4 inches on March 31 or 96% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 52.3" (30-year normal)
• 1982-1983: 68.9”
• 1986-1987: 58.5"
• 1991-1992: 34.4"
• 1997-1998: 55.0"
• 2002-2003: 44.0"
• 2009-2010: 42.0"
• 2015-2016: 50.0"

Three out of the seven El Niño years produced above normal snow water equivalent (SWE) on Mt Hood on March 31.

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...

• November: 2.1" (230%) 
• December: 8.6" (139%) 
• January: 10.7" (97%)
• February: 10.6" (95%)
• March: 8.0" (93%)
• April: 9.7" (94%)

It tends to be that the early season (Nov-Dec) is more likely to be above normal, while mid to late season (Jan-Apr) is more likely to be normal to slightly below normal. 

Historical El Niño Seasons @ Mount Bachelor

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 35.9 inches at the Mckenzie SNOTEL near Bachelor. I've found that the median SWE near Bachelor during those El Niño years is 34.9 inches on March 31 or 83% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 35.9" (30-year normal)
• 1982-1983: 34.6”
• 1986-1987: 34.7"
• 1991-1992: 13.3"
• 1997-1998: 30.0"
• 2002-2003: 33.0"
• 2009-2010: 27.3"
• 2015-2016: 34.9"

Zero out of the seven El Niño years produced above normal snow water equivalent (SWE) near Bachelor on March 31. Despite that, the amounts were very close to the normal for four out of the seven El Niño years.

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...

• December: 6.8" (129%) 
• January: 8.3" (91%)
• February: 6.3" (84%)
• March: 4.6" (79%)
• April: 3.5" (83%)

Similar to Mt Hood, Mt Bachelor tends to be that the early season (Dec) is more likely to be above normal, while mid to late season (Jan-Apr) is more likely to be near normal or below normal.

Historical El Niño Seasons @ Hoodoo

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 21.7 inches at the Hogg Pass SNOTEL near Hoodoo. I've found that the median SWE near Hoodoo during those El Niño years is 25.0 inches on March 31 or 115% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 25.0” (30-year normal)
• 1982-1983: 27.9”
• 1986-1987: 38.6"
• 1991-1992: 11.8"
• 1997-1998: 35.1"
• 2002-2003: 24.0"
• 2009-2010: 21.7"
• 2015-2016: 16.2"

Three out of the seven El Niño years produced above normal snow water equivalent (SWE) near Hoodoo on March 31.

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...

• December: 5.9" (183%) 
• January: 6.2" (108%)
• February: 7.0" (134%)
• March: 3.9" (140%)
• April: 1.9" (114%)

Hoodoo tends to see a little bit of everything with an above normal start to the season (Dec). There is a decline closer to normal mid to late season (Jan-Apr), yet still staying above normal. 

Historical El Niño Seasons @ Mount Ashland

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 25.2 inches at the Big Red Mountain SNOTEL near Mt Ashland. I've found that the median SWE near Mt Ashland during those El Niño years is 30.8 inches on March 31 or 122% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 25.2” (30-year normal)
• 1982-1983: 59.0”
• 1986-1987: 27.3"
• 1991-1992: 12.7"
• 1997-1998: 34.9"
• 2002-2003: 28.5"
• 2009-2010: 24.3"
• 2015-2016: 29.2"

Five out of the seven El Niño years produced above normal snow water equivalent (SWE) near Mt Ashland on March 31.

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...

• December: 3.2" (100%) 
• January: 8.4" (125%)
• February: 6.4" (119%)
• March: 6.6" (117%)
• April: 6.0" (117%)

Mt Ashland is a little bit of a different animal than other resorts in Oregon during El Niño. The early season (Dec) is more likely to be normal, while mid to late season (Jan-Apr) is more likely to be above normal.

Mt Ashland tends to see more snow than other parts of Oregon during El Niño because it is the closest resort to California. California generally sees above normal snow during El Niño because of the increased frequency of atmospheric rivers. 

Historical El Niño Seasons @ Anthony Lakes

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 Wolf Creek SNOTEL near Anthony Lakes. I've found that the median SWE near Anthony Lakes during those El Niño years is 15.3 inches on March 31 or 97% compared to the 30-year normal.

SWE on March 31 During El Niño

• 1991-2020: 15.8” (30-year normal)
• 1982-1983: 24.6”
• 1986-1987: 14.5"
• 1991-1992: 7.8"
• 1997-1998: 19.6"
• 2002-2003: 11.7"
• 2009-2010: 11.8"
• 2015-2016: 16.8"

Three out of the seven El Niño years produced above normal snow water equivalent (SWE) near Anthony Lakes on March 31.

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...

• December: 2.8" (128%) 
• January: 4.9" (137%)
• February: 2.5" (100%)
• March: 3.2" (100%)
• April: 1.8" (95%)

It tends to be that the early season (Nov-Dec) is more likely to be above normal, while mid to late season (Jan-Apr) is more likely to be normal to slightly below normal.

Temperatures During Significant El Niño Winters

While snowfall is what we pay attention to the most during ski season, temperatures are also a factor in terms of snow quality. It is especially important in Oregon where snow levels can be a significant factor in the winter season. 

I examined NOAA’s, National Center for Environmental Information (NECI) Climate Division dataset, which takes in station observations throughout the United States. A quick look at the NOAA/NECI map below for the El Niño winters analyzed above shows above normal temperatures for all of Oregon.

 

The temperature anomalies are not as warm as other parts of the PNW, which explains the near normal snowfall totals for many areas of Oregon during El Niño winters. 

2015-2016 El Niño Season

The most recent El Niño in 2015-16 produced normal to above normal snowfall across Oregon. The map below shows the March 31, 2016 basin average snow water equivalent (SWE) anomaly. 

This map uses SNOTEL and other station data to create a hydrologic basin-wide average. 

Overall, history tells us that Oregon tends to be right around average for snowfall during El Niño winters, with the potential for a stronger start and weaker end to the season. Southwestern Oregon tends to do better because of the influence of atmospheric rivers during El Niño winters. 

An additional factor in the El Niño winters analyzed above is that they can be variable. While the average is near normal, several seasons were on the extreme ends of low to high snow seasons. While the statistics above are using the seven past El Niño winters, every winter can be different and will have its own unique impacts.  

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

Zach Butler