Gateway to the Arctic: Historic heat in Canada

At the gateway to the Arctic, Canada is experiencing record temperatures, well above the usual seasonal averages.

Several Canadian regions, despite being used to harsh winters, are experiencing temperatures as high as 69 degrees in the middle of January. This is very close to the absolute record for a month of January for the whole of Canada, which is 71.9 degrees F (22.2°C), measured in January 1950.

A key factor in triggering these record temperatures is a phenomenon known as the Pineapple Express, which generally brings very mild winter weather to British Columbia.

This is a mass of warm air from the Pacific Ocean, enriched with moisture from the Hawaiian Islands, with temperatures aloft more than 10 degrees higher than normal.

El Niño has also generated a powerful subtropical jet stream associated with intense atmospheric river events along the west coast of North America, hence the origin of this warm air mass.

Downstream of this model, an anomalous anticyclone has developed in the heart of the Prairie provinces. The air descending from the Rockies compressed and warmed, contributing to the rise in temperatures.

Numerous monthly records were broken, such as Nordegg in Alberta with 60.6 degrees F (15.9°C), beating the previous monthly record set in 2001. There was also a record high of 59.5 degrees F (15.3°C) at Hendrickson Creek, also in Alberta, which had not seen such temperatures since January 1996.

In the Yukon, a territory in north-western Canada bordered to the west by Alaska, records were also broken at Watson Lake, where the temperature rose to 50 degrees F (10°C), setting a new record for the period.