British Columbia’s late June heatwave that saw temperatures rise above 40 C continues to have devastating impacts on the province’s water supply.
According to the Vancouver Sun, low spring rainfall combined with the recent heatwave is causing water scarcity and low flows throughout the province. Vancouver Island and the B.C. Interior are experiencing severe scarcity, with the East Vancouver Island Basin and Kettle River Basin having hit Drought Level 4, the second-highest drought designation in the province.
An interactive drought map similarly shows dry conditions throughout much of the province — with the towns of Creston, Kootenay Landing, and Sirdar classified as experiencing severe drought.
“My understanding is that [current conditions] are related to a stalling of the jet stream,” says Daniel Moore, a geography professor at the University of British Columbia whose research specializes on the influence of climate change on hydrological processes and the pattern of streamflow.
“The jet stream develops what are called Rossby waves, a wave-like pattern in the jet stream, and they tend to migrate around the circumpolar region [within the Arctic and Antarctic circles]. Under situations like we have now, the wave-like pattern in the jet stream stalled out and [became] relatively stationary, and that sets up this persistent high-pressure system that we’re experiencing.”
Moore says this phenomenon has also affected the rate of glacier melt, which could increase the severity of future droughts.
“Glaciers have a really interesting role when you have these periods of hot dry weather, because they’re essentially big reservoirs of ice,” says Moore.
“The weather conditions tend to accelerate the melt of the glacier, which keeps the rivers cool and full of water.”
While visiting a field site last week, Moore says that the accelerated melting of a nearby glacier had impacted the flow of a creek that Moore and his team typically cross to get to their normal camping site.
“We’ve never had trouble wading that stream,” Moore says. “This trip, it was impassible, because the glacier [was] melting at such a rapid rate that the flows were really high, and it was way too dangerous to try and cross.”
According to Oliver Brandes, an adjunct professor at the University of Victoria’s faculty of law and School of Public Policy, this combined with previous water shortages indicates that this will be a recurring issue, which means that the province will need to rethink its long-term water strategy.
“We’ve seen over the last 20 years, an intensification of droughts… even in the last five years, we’ve probably had three or four pretty serious drought episodes in different regions in the province.”
Reservoirs, says Brandes, will need to be watched particularly closely, as those connected to higher usage will be at risk of running out.
“In the past, a few places like the Sunshine Coast and Gibsons came very close to running out of water,” says Brandes.
“So, I think it means two things. [Regional districts] have to think in a much more resilient frame about the future as droughts become routine, and what are the different ways we can reduce our water use, both generally and what to do when the time cranks up.”