Good news for powder hunters and ice climbers: La Niña conditions will bring a snowy and cold winter to much of Alberta, and it could last into the spring.
According to the most recent predictions statement issued Nov. 30 by the National Oceanic and Atmospheric Administration (NOAA), there is a 95 per cent chance that La Niña will persist until March and a 65 per cent chance that it could stretch into May.
What is La Niña
La Niña — Spanish for “little girl” — is when water temperatures become cooler-than-average in the eastern Pacific Ocean near the equator. The change in sea surface temperatures can create large-scale changes in upper airflow around the globe and have major impacts on our local weather.
La Niña and the opposite, warmer phase, El Niño (“little boy”) are natural ocean-atmospheric phenomenons in the El Niño-Southern Oscillation (ENSO) cycle. When neither climate pattern is present, the ENSO is neutral and does not influence airflow.
The cold phase can last nine months to a year, and while the frequency of ENSO phases can vary, La Niña is less common than its sibling, El Niño.
What does La Niña mean for Alberta?
In short, a strengthening La Niña pattern means colder and snowier conditions can be expected across the Prairies this winter season.
Ski season has already kicked off earlier than usual in Alberta and powder hunters will be happy to hear that rounds of snowstorms will continue to bring plenty of snow to the mountains. However, this could also result in prime avalanche conditions and a higher risk for those enjoying the backcountry.
As for temperatures, La Niña’s influence on the jet stream means more waves of Arctic air pushing down into the province. Northern Alberta, and as far down as the Edmonton region, will likely deal with the brunt of the Polar Vortex. Whereas Calgary and southern Alberta will get some bouts of relief from the cold with Chinooks blowing in warmer weather.
It’s important to note that, along with sea surface temperatures, there are many other elements — like blocks in our jet stream — that can develop and influence our weather throughout the season. Therefore, looking at how a La Niña pattern typically affects our province and forecast should only be taken as a guideline.
The last time we experienced a La Niña winter was the 2017-2018 season. The following winter, the El Niño phase dominated and then last year, we were ENSO neutral.