Heat wave had 'worrisome' impact on B.C.'s glaciers, expert says
Early snowmelt leaves glaciers exposed to heat longer and leads to lack of runoff, affecting hydro, ecosystems
Last week's unprecedented heat wave in British Columbia has harmful implications for the province's approximately 17,000 glaciers, a leading Canadian expert says.
According to Brian Menounos, Canada research chair in glacier change, rapid snowmelt this early in the summer means glaciers will be exposed to warmer weather longer without that buffer of snow.
In addition, those glaciers usually feed headwater streams with fresh water in late summer, and not having that runoff because of the early melt could affect ecosystems and hydropower capacity, said Menounos, a geography professor at the University of Northern British Columbia
"That much energy and that much heat throughout the province over all of the glaciers was quite worrisome," he told CBC's The Early Edition on Thursday.
"The glacier runoff tends to start to supplement some of our headwater streams in late summer, typically end of July. We're seeing that starting much earlier this year, unfortunately, due to the heat dome."
Menounos said regardless of the heat dome — which led to almost 60 temperature records being broken in the province including an all-time Canadian high of 49.6 C in Lytton, B.C. — glacier melt is already happening at an unsustainable level.
"What's truly alarming is how quickly some of these small glaciers are disappearing and the implications for this glacier loss," said Menounos.
He said the implication for hydroelectric power in some areas is substantial and, in some cases, the loss of glaciers could mean the potential loss of sensitive aquatic ecosystems.
How unusual were temperatures at the top of BC's glaciers during <a href="https://twitter.com/hashtag/heatdome?src=hash&ref_src=twsrc%5Etfw">#heatdome</a> ? Simply put, off the chart. Here's daily Temperatures [1979-2021] at 700 hPa (about 3000 m asl) over Lillooet Icefield from <a href="https://twitter.com/ECMWF?ref_src=twsrc%5Etfw">@ecmwf</a> ERA5 reanalysis. Red dots are daily temps of last 14 days. <a href="https://t.co/TOXH4YgToF">pic.twitter.com/TOXH4YgToF</a>—@brianmenounos
A 2015 study published in Nature Geoscience predicted that 70 per cent of glaciers in Western Canada will be completely gone by 2100 — and that the fastest rate of ice loss, corresponding to higher rates of meltwater to rivers, will happen from 2020 to 2040.
This melt also contributes to flooding.
The B.C. River Forecast Centre called the amount of snowmelt at the higher elevations "astounding" during the heat wave and flood warnings were in effect for many parts of the province during the last days of June.
"Please be advised that with the extreme hot weather, river levels are extremely high," officials for Mount Robson Provincial Park in B.C. warned on June 30.
On July 1, three hiking trails, including the highly popular Berg Lake trail by Mount Robson, needed to be closed because of damage from flooding waters.
Menounos also warned that as glaciers melt and retreat, they can create instability in steep slopes that can cause dangerous landslides.
WATCH | Brian Menounos explains connection between melting glaciers and landslides:
"I would say the Coast Mountains [are] an area that we have to keep our eye on and certainly there's a lot of people that live in those communities," he said.
The heat wave that blanketed B.C. also crossed the Rocky Mountains and warmed up Alberta.
Using data from the Agriculture and Forestry Department of Alberta and Environment Canada, University of Alberta glaciologist Jeffrey Kavanaugh estimates that the resulting melt from glaciers in the mountains during the same 10-day period was about three times higher than normal, compared with the past 12 years.
LISTEN | Menounos talks to CBC's The Early Edition host Stephen Quinn about glacier melt:
With files from The Early Edition and Sarah Moore