Calgarians have experienced a winter marked by sharp swings between mild and cold conditions, including temperatures reaching 18 C in March.
Rather than consistently cold weather and snowfall, this year’s winter months were marked by extended warm spells and sudden temperature drops.
January contributed to this season’s weird weather.
It was Calgary’s 17th-warmest January of the last 143 years, with an average temperature of -3.4 C.
Typical Calgary winter weather
Typically, the average temperature in Calgary for the month of January is -7.6 C, according to Environment and Climate Change Canada.
“It was pretty notable how warm it was in Calgary across the month of January,” said Alysa Pederson, a meteorologist with Environment and Climate Change Canada.
The city also recorded 13 days with temperatures above 10 C between January and mid-February, more than double the five-year average of six days. Calgary also saw four days above 15 C, tying a record for that period.
According to Pederson, much of the warmth was associated with an upper-level ridge pattern in which the jet stream has been displaced to the north of Alberta, allowing warmer air to accumulate over the area.
“When that jet stream moves north of us, all the storm systems go north as well,” she said.
The pattern has continued into March, with temperatures reaching 18 C before shifting back to colder conditions.
According to Pedersen shift restricted the amount of snowfall over most of Alberta, even though northern regions received increased precipitation.
The chinook effect
Chinook winds are a factor in some of the warmth observed on those days, but Pederson said a larger-scale atmospheric pattern was responsible for most of the warmer conditions.
The warmth, however, has not been consistent. More recent cold temperatures have reinforced how variable the winter has been.
“The winter has been extraordinarily variable,” said John Pomeroy, a hydrology professor at the University of Saskatchewan.
Pomeroy remarked that varying conditions can be observed in the Rocky Mountains, depending on elevation.
While higher elevations have received more than usual precipitation, including significant snowfall, lower elevations have had warm spells and some rainfall, resulting in slight melting and inconsistent snow cover from one area to another.
“Calgary has experienced a colder version of what the mountain valleys experienced,” he said.
The milder weather has been welcomed by many, but experts say it comes with trade-offs.
Increased risk of fire
Spring will have a lower-than-expected snowpack, which increases the risk of fire during the “spring dip,” the period between snowmelt and the return of vegetation.
Pomeroy said this type of winter — combining warmer temperatures with fluctuating precipitation — aligns with climate projections.
“This sort of weather is consistent with what climate change models have predicted for the mid-21st century,” he said.
Pederson cautioned that a single season does not define climate trends.
“In isolation, one year isn’t going to give a clear picture,” she said.
However, she said longer-term patterns show increasing variability, with more frequent swings between extreme warmth and cold.
Pomeroy said those changes could affect water systems in Alberta.
Earlier snowmelt may cause river levels, including the Bow River, to peak earlier in the year, leading to lower summer water levels.
“This is already starting to happen,” he said.
