La Niña Is Strengthening, Potential Winter 2022-2023 Impacts
Article courtesy of Open Snow, Sam Collentine, Meteorologist
For the upcoming winter season, a “Triple Dip La Niña” looks to be in-store and better yet, current sea surface temperatures are showing a robust La Niña event. This article will explain what exactly La Niña is and what a significant La Niña episode could mean for the 2022-2023 ski season.
What is La Niña?
The term La Niña refers to the large-scale ocean-atmosphere climate phenomenon linked to periodic cooling in sea-surface temperatures across the central and east-central equatorial Pacific.
La Niña represents the cool phase of the ENSO cycle and means that the ocean water temperatures are cooler than average.
La Niña Criteria
1) The average sea surface temperatures in the Niño-3.4 region of the equatorial Pacific Ocean were at least 0.5°C (0.9°F) cooler than average in the preceding month.
2) The average anomaly of at least -0.5°C (-0.9°F) has persisted or is expected to persist for five consecutive, overlapping 3-month periods.
Current La Niña Status
Confidence is growing that a third consecutive La Niña will occur this winter – something that meteorologists have termed a “Triple Dip La Niña”.
A La Niña pattern has persisted into the summer of 2022, and long-range models have been projecting a higher than average chance of a La Niña continuing into the winter of 2022-2023, before possibly weakening in the spring of 2023.
The weekly Nino-3.4 region index (sea surface temperatures in the east-central Pacific) anomaly is down to -1.2°C. This is the coldest weekly SST anomaly in August since 2010.
How predictable are the impacts of La Niña?
There are two major sources of uncertainty in long-range forecasts predicting weather months in advance.
The first source of uncertainty is how accurately we can predict La Niña or El Niño. La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% to 60% during the December 2022 to February 2023 timeframe.
The second source of uncertainty is the atmospheric response to La Niña or El Niño. That is, if La Niña occurs, does it always affect weather in North America in the same way?
To determine how La Niña impacts weather in North America, we can look at snowfall records during past La Niña events and compare them to a typical year.
Historical La Niña Episodes
The map below shows winter snowfall during seven significant La Niña episodes. The lower the number, the stronger the La Niña. The blue dots are above-average, the white dots are average, and the orange dots are below-average snowfall.
The effects of La Nina appear to show much of the Western US receiving average to above-average snowfall during these significant events. Again, though, the pattern doesn’t hold 100% of the time.
2010-2011 Winter Season
As mentioned above, the Niño-3.4 region index anomaly as of August 21, 2022, is down to -1.2°C, which is the coldest weekly sea surface temperature anomaly in August since 2010 (-1.17° in 2010 vs. 1.2°C in 2022).
Since the last significant La Niña episode occurred back in 2010, let’s have a little fun by looking back at the snowfall during the 2010-2011 winter season at ski resorts across the Western US, which was a banner year for many areas.
All data is courtesy of BestSnow.net
- Kirkwood: 802″ (170% of normal)
- Palisades Tahoe: 783″ (173% of normal)
- Mammoth: 652″ (183% of normal)
- Crystal Mountain: 581″ (147% of normal)
- Mt. Hood: 620″ (140% of normal)
- Mt. Bachelor: 630″ (168% of normal)
- Whitefish: 425″ (133% of normal)
- Jackson Hole: 539″ (146% of normal)
- Sun Valley: 250″ (131% of normal)
The 2010-2011 ski season is interesting to look at as a potential comparison for a significant La Niña episode but keep in mind that no matter how deep or light a winter is overall, when it comes to skiing, it’s all about timing.
Booking a trip 7-10 days in advance and for a general area that looks stormy will increase your chances of scoring deep powder days.
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