Rainfall easing immediate drought concerns in southern Alberta, but more precipitation needed

While rainfall is helping ease short-term drought concerns in southern Alberta, the region will need much more precipitation to keep moisture levels sufficient through the summer.

Brian Proctor, an Environment and Climate Change Canada meteorologist, said recent precipitation in Calgary has moisture levels trending in the right direction.

"It's not necessarily solving any issues, but it's helping to address some of the shorter-term concerns," Proctor said during an interview on Wednesday.

Calgary has seen measurable precipitation 16 out of 22 days in May, according to the weather station at the airport.

"Which is astounding, really, when you consider how dry it was earlier in the year," Proctor said.

With moderate to extreme drought conditions predicted in southern Alberta, Proctor said precipitation is helping tone those levels down slightly right now – but more moisture will be needed to get the province through the summer.

"Maybe we're improving it one category or so, but we're still looking for significant potential for drought out there on the landscape," he said.

"We're addressing short-term concerns but longer-term, we still need much, much more moisture than we've seen to really alleviate our long-term concerns."

High soil moisture is good news for dry land farmers, according to John Pomeroy, director, Global Water Futures Programme and USask Centre for Hydrology.

"It's up to 150 per cent from normal for Calgary, into southern Alberta."

River water used for cities and irrigation has improved as well, since the mountains have been getting precipitation, too, taking concerningly low snowpack levels up to about average.

"It looks like we will be out of the severe hydrological drought that we had," Pomeroy said. 

He says the Oldman River is the exception, with river levels not expected to benefit irrigation in that area. 

Despite a rainy May, the City of Calgary is still encouraging Calgarians to be mindful of their water use, especially outside.

"Based on the significant regional precipitation and cool temperatures we've experienced thus far this spring, drought conditions have improved for Calgary and the region, but we must remain prepared," the city said in an emailed statement on Wednesday.

"It's still early in the season and the summer could bring prolonged periods of hot, dry weather that could impact Calgary's water supply."

The city encourages residents to avoid watering if there is rain in the forecast, or after it's rained; only water in the early morning or evening and limit sprinkler use to four hours a week or less.

Flooding is still a risk for southern Alberta throughout the late spring and early summer, even with a dry start to the year.

"From May 15 to July 15 is the time when we can get those really big rains, and so that's why the city is on high alert during that season," said Sandy Davis, leader of river engineering with the City of Calgary.

With precipitation increasing as Calgary enters into flood season, the city said it is continually monitoring the weather and river levels.

"What drives flooding in Calgary are big rains in the mountains and the foothills," Davis said.

"As we see the snowpack accumulating and starting to melt through May, that tells us a lot about the water supply through the summer, it starts to raise our river levels in spring, but snow melt alone doesn't drive river flooding, so what we're really watching for are the big rain systems and those can be challenging to predict in advance."

Snowpack in the Rockies is starting to provide a delayed release of moisture, but Proctor said more is still needed. Banff has seen nine days of precipitation in May so far.

"As we move into what typically is the warm and dry part of our year, which is removed out of May and June, in towards the summer, we need more moisture," Proctor said.

Proctor is predicting a "more normal" summer temperature-wise for southern Alberta, as the effects of El Nino wane.