Snow drought in southern Alberta raises concerns for spring
Monday, January 14, 2019, 5:44 PM - Temperatures soared into the mid-teens across southern Alberta last weekend, smashing records and sending many out to bask in the mid-winter sunshine. While a major cool-down is on the way for this week, one thing that doesn't feature in the forecast -- and hasn't for much of the winter thus far -- is snow. A gentle winter may sound appealing, but there are growing concerns that the lack of winter snow pack, and one of the causes behind it, may have some serious implications for the spring and summer growing seasons.
Winter 2018-2019 got off to a banner start for much of southern Alberta, with Calgary reporting nearly 50 cm of snow in October and close to 30 in November -- well above the usual 26 cm average for the two months -- winter snow fall has more or less abandoned the southern tier of the province since then. Couple that with repeated blasts of Chinook winds, and you're looking at a lot of bare, dry ground across the region.
(Related: Winter 2018-2019 Official Forecast update)
The image below shows the precipitation deficit for the winter season so far across the Prairies. The spreading tan and brown colours are part of what's raising concerns for spring and summer farming conditions. Rain and snowfall in southern Alberta is running about 20 to 30 mm below average for the winter as a whole, with more significant deficits building over southern Saskatchewan and Manitoba.
How does that mesh with the strong early start to winter? Take a look at the map below, which shows the deficit for the past thirty days. Dry conditions in December and early January extend even further into central Alberta, creeping up toward Edmonton, while the extent of the 20 to 30 mm below spreads much further.
WHAT'S BEHIND THE DRY WEATHER?
In the 2018-2019 winter forecast, Weather Network meteorologist Dr. Doug Gillham highlighted a drier, milder winter for southern Alberta. While the main influence behind that forecast was closer to home -- namely, 'The Blob' temperature anomaly off the coast of British Columbia -- the more famous (or perhaps infamous?) El Niño phenomenon also plays a role, and one that will become more pronounced as we head toward spring.
The latest update from NOAA's Climate Prediction Center (CPC) note that, while the expected El Niño has yet to form, chances are still good that we will see warmer-than-average sea temperatures develop off the coast of South America going into the spring. While the CPC doesn't forecast a strong El Niño, it can still have an impact on western North America's weather patterns for spring and summer; namely, in the form of drier- and milder-than-average conditions.
That lack of moisture could also spell another active wildfire season for the province. Alberta's wildfire season officially begins March 1.
“I think we could wind up having one of the hottest summers,” said Mary-Ellen Tyler, a professor with the University of Calgary’s faculty of environmental design told Global News. "That will exacerbate any precipitation we have because those temperatures usually come with very high evapotranspiration or drying rates in Alberta, so I’m thinking we’re still in a moderate drought situation."
Last year, Tyler told CBC News that this dry state may be "the new normal" for Alberta. "It's not a crisis right now, but it's building to a different threshold that we need to start planning for," Tyler said. "It isn't going to be 50 years between droughts. We're going to be moving into a more constant state of dry."