CBC Alberta and Saskatchewan have teamed up for a new pilot series on weather and climate change on the prairies. Meteorologist Christie Klimenhaga will include her expert voice in the talk to help explain meteorological phenomena and climate change and how they affect daily life.
Our climate is constantly changing with a tendency towards higher average temperatures, especially in recent decades.
But within this constant ascent, of course, we have variations.
One of the biggest predictable changes in a region’s climate is El Niño and La Niña. In Spanish, the words mean little boy and little girl; over time, they are climate models in the Pacific that can affect weather conditions around the world.
The climate acts as a pendulum swinging from the conditions of El Niño, through neutral, then to the conditions of La Niña. Sometimes the pendulum is faster, sometimes slower.
But what happens when the pendulum crashes?
We can understand this winter. Forecasts point to the chance of a “triple decline” – that is, the third consecutive – La Niña winter.
We are currently in the situation of La Niña and we have winters in La Niña from 2020.
According to the latest report from the World Meteorological Organization (WMO), La Niña has a 70 percent chance of continuing in the summer and a 50 to 60 percent chance of continuing until the end of the year and until another winter.
But what does this mean for our time locally? And what about the multi-million dollar question: what role does climate change play?
What is La Niña?
La Niña means that the ocean waters on the surface of the eastern Pacific are colder. This is the opposite of El Niño, where these water temperatures are warming.
The indicator for declaring El Niño or La Niña is half a degree above or below the long-term average, but it can, of course, be more significant than that. Nevertheless, this innocent-sounding change could have a major impact on the Pacific coast as well as globally.
La Niña has lower-than-usual temperatures in the Pacific, which could lead to weather changes in western Canada. (The Weather Network)
According to the WMO, ocean cooling can cause changes in tropical atmospheric circulation, mainly with winds, pressure and precipitation.
“When there is La Niña, it is usually followed by droughts in East Africa and droughts along the Gulf Coast. And floods in other parts of the world, such as West Africa,” said Wilfran Mufuma Okia, head of regional services. WMO Climate Forecasting in Geneva, Switzerland.
But these cold ocean waters also play with our Canadian time.
During the La Niña years, the jet over North America often shifted further north, causing changes in temperature, traces of storms and rainfall, especially during the winter months.
“This usually means cooler than normal for much of western Canada and wetter than normal in southern BC, near the coast,” said Nathan Gillette, a researcher in the environment and climate change. in Canada.
La Niña with triple immersion are rare
Although La Niña varies in length and strength, if it is carried over to another winter, it will be the third La Niña with a triple immersion since 1950, according to the WMO.
“It’s rare,” says Gillette.
But this is not unheard of, adds Mufuma Okia.
“This La Niña episode is not unprecedented in terms of length,” he said.
The Canadian impact of La Niña
In the past, our winters in La Niña meant wild weather for Western Canada.
La Niña often means cooler winters in Alberta and Saskatchewan and wet weather off the west coast. (Christie Klimenhaga / CBC)
In the winter of 2010-11, during particularly heavy La Niña, heavy snowfall dominated western Canada, with the Alpine resort of Mount Washington on Vancouver Island seeing more than 500 centimeters of snow by the end of December.
This La Niña also meant low winter temperatures on the prairies and heavy snowfall in Alberta, where Edmonton saw nearly 160 centimeters of snow between October 2010 and March 2011. The capital of Alberta usually saw about 85 centimeters during this time.
During a three-year event in La Niña in the late 1990s, storms brought record snowfall.
A record 145 centimeters of snow – about 4.75 feet – fell in one day on Lake Tahtsa, located on the coast of British Columbia, about 120 kilometers southeast of Terrace, according to Environment and Climate Change Canada The storm on February 11, 1999 was accurate in the middle of this three-year-old La Niña.
Climate change and La Niña
The connection between climate change and our conditions in La Niña is a bit complicated, says Mufuma Okia.
There is no clear link between more affected areas and climate change, he said. But by 2050, precipitation is expected to change.
“There will be extreme rainfall in places where we usually have the impact of La Niña or El Niño,” he said.
Gillette adds that while El Niño and La Niña will continue in the future, our neutral state between the two may begin to change warmer.
“It is expected to remain the dominant mode of variability,” he said. “The kind of support is expected to change slightly to conditions similar to El Niño.”
Our planet is changing. So is our journalism. This story is part of the CBC News initiative, entitled “Our Changing Planet”, to show and explain the effects of climate change. Keep up to date with the latest news on our climate and environment page.
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