Climate change means more rain will fall but its impact on severe storms is less clear

CBC Alberta and Saskatchewan have teamed up for a new pilot series on weather and climate change on the prairies. Meteorologist Christy Climenhaga will bring her expert voice to the conversation to help explain weather phenomena and climate change and how it impacts everyday life.

Severe thunderstorms and summer go hand-in-hand on the Prairies. And it's not your imagination that such weather events have been getting increasingly catastrophic over the past decade.

In the prairies, the last few years have been marked by severe storms. Calgary alone has seen hail, funnel clouds and lightning strikes, with downpours that turned roads into rivers and stranded motorists in their cars. 

Climate change is increasing the risk of these extreme weather events. 

In fact, "extreme weather presents the most immediate climate risk for the Prairie provinces, as is evident from the catastrophic events that have taken place over the past 10 years," according to a report from Canada in a Changing Climate, a federal government-led partnership of climate change experts.

But where do these severe storms fit into the climate change puzzle? 

The answer is complicated. In some places, science shows a clear cause-and-effect. But other elements are more up in the air.  

A major factor of climate change on storm severity is the impact of warmer summers on our water cycle.

Warmer temperatures mean more evaporation (where liquid water is transformed into a water vapour) and transpiration (where water is sapped from vegetation). Because warmer air can hold more moisture, our storm systems will have the potential for heavier rainfall because of all that extra water.

Systems like our Alberta Clippers (those fast-moving, low pressure systems that rip across the prairies), or atmospheric rivers (those channels of moisture in the atmosphere that bring constant rain to the coasts), or even our run-of-the-mill thunderstorms could see those risks of higher rainfall amounts.

So though we know that climate change is increasing our risk of drought conditions and wildfire, it also increases our risk of high precipitation events. 

And even though it sounds counterintuitive, these extremes can exist simultaneously.

"Given the vast size and hydroclimatic diversity of the Prairie provinces, it is not unusual for parts of the region to be experiencing drought and wildfire at the same time, while other communities are being flooded," states the Regional Perspectives report from Canada in a Changing Climate.

Think about spring 2011 when a wildfire ripped through Slave Lake, Alta., while further east, a one-in-350-year flooding event devastated properties near the Assiniboine River in Manitoba.