This is a second part in a series on the potential impacts of climate change through the seasons.
Last June it rained 27 out of 30 days in Revelstoke. Across the Columbia Basin, rainfall records were broken. Landslides caused by the high rainfalls destroyed homes and roads. Reservoirs filled with so much water to the point that BC Hydro had to open the spill gates at both Revelstoke and Mica Dams for the first time in decades.
While last June’s rain was an extreme occurrence, it could be a sign of things to come, according to a climate change report by the Columbia Basin Trust.
The report, Climate change, impacts and adaptation in the Canadian Columbia Basin: From dialogue to action, was published last fall. It makes a detailed breakdown of the impacts of climate change, and provides suggestions on how people, communities and industries can adapt.
According to the report, spring temperatures throughout the basin are expected to climb, as is spring precipitation. More intense storms are also expected, meaning heavier rainfall when it does come.
That means the rains that caused landslides that destroyed homes in Johnson Landing and wiped out sections of highway near Sicamous could be more frequent.
“More frequent intense rainstorms, increased glacier melt, rain-on-frozen ground, rain-on-snow and higher winter peak flows may increase the risk of flooding, with more events occurring in late winter/early spring than in the past,” says the CBT report.
The effects of climate change could lead to big infrastructure challenges for people, businesses and communities. Hydro reservoirs will possibly start filling up earlier, fill up with more water, and have to contend with big spring rain events.
On the positive side, the growing season will be longer – a boon for farmers and gardeners – and an earlier snow melt will make communities more accessible for people that struggle with mobility, like seniors and the disabled.
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The impacts of climate change on spring will start earlier in the season. It is expected the season will start earlier in the Columbia Basin. Projections prepared by the Pacific Climate Impacts Consortium at the University of Victoria indicate springs will be warmer and wetter, though as PCIC climate scientist Trevor Murdock told me, the projections are for ranges, meaning that any given spring will be different. Other climate factors, like El Nino and La Nina also play a role from year-to-year.
“There’s a range in the projections and it’s hard to talk about,” he said. “It’s not uncertainty in the sense of not knowing, it’s uncertainty in the sense that what we know with a good deal of certainty is the change in the 30-year average.”
Practically, snowpacks are expected to increase at higher elevations over the coming years, though more rain is expected to fall in valleys throughout the winter. Springs will come earlier and also be wetter in the future than today.
“You may have earlier springs, in general, but larger spring peaks because of having larger snowpack during the winter,” Murdock said. “You have an earlier peak, a drier dry season, and longer dry season, but then a wetter wet season.”
For long-term planners like forestry professionals and municipal planners, the broad range gives a useful idea of what to expect. For individuals, saying what the average spring will look like is much harder due to the range of projections, said Murdock.
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Cindy Pearce was part of the team that worked on the Columbia Basin Trust report. She wears a number of hats as a consultant, but in her role here, she referred to herself this time as a “rural community climate change resilience facilitator.” She helped walk me through some of the real world changes we might see if climate changes bear out, much of which is detailed in the CBT report.
Among the impacts she mentioned are:
– A longer growing season. The CBT report says there could be anywhere from 18 to 35 more growing days by 2050, compared with the baseline 1971-200 period. This means crops that require a longer growing season can be planted. On the downside, there is still a risk of frost events, which could kill plants. As well, “Plants start to grow and to flower earlier and they aren’t always in synch with the insects that help them pollinate, so things get out of synch,” she said. “It could have a negative impact on fruiting.”
– Higher peak flows. More precipitation means more water and bigger spring freshets. “It can cause flooding,” she said. “It can cause the kind of debris flows that we saw last year and it can damage habitat for fish species, and wetlands and those kind of things.” It can also impact roads due to increased risks of landslides.
– Industries like logging will be impacted by shorter winters and longer springs. “Winters are shorter, so you’re getting a squished winter logging season,” said Pearce. The spring meltdown could be longer, though summer logging season could be longer too. Like other areas, the industry will be impacted by infrastructure challenges on logging roads due to heavy rain.
– City infrastructure, especially water and sewer systems will face pressures, though that will be more of an issue in the summer, when drier conditions are expected. “We need to have enough water stored up or ensure we have enough flow to service our needs over the summer,” said Pearce. As well, the CBT reports says that communities may experience “increased flooding and sewer backups in heavy rainfall events,” and “extreme events such as landslides, wildfires or windstorms have the potential to cause significant infrastructure damage.” This could lead to increased maintenance and insurance costs for everyone.
– Tourism will change. An earlier snow melt means winter sports like snowmobiling and skiing will be affected. “We haven’t had to do this yet, but the snowmobile folks may need to move their parking lot further up the hill so they can access snow longer,” she said. On the positive side, spring and summer tourism providers can start their seasons earlier, though extreme rain events, flooding and landslides could impact recreation infrastructure.
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It also means changes in reservoir management, as reservoirs fill up faster. For that topic, I spoke to Stephanie Smith, the manager of hydrology and technical services with BC Hydro. She has been giving presentations on the impact of climate change on BC Hydro reservations recently.
BC Hydro published its own report on climate change last year. It made similar conclusions to the CBT report – warmer weather and more precipitation. Inflows into the Columbia River are expected to increase, though by how much is uncertain. Shrinking glaciers means there will be less inflow from glacial melt, but that will be more than offset by increases in precipitation. As well, more inflow is expected in the late winter and spring, and less flow is expected in the summer.
What will this mean for BC Hydro? The report doesn’t answer that, instead leaving the question open for future study.
“The next step for BC Hydro is to feed operational and planning models with projected inflow scenarios to assess how sensitive hydroelectric power generation is to climate change,” the report concludes. “For instance, it has not been determined how effectively reservoir storage will be able to buffer projected changes in seasonal runoff timing, such as lower summer inflows.”
“We’re still sorting that out,” Smith told me. “A lot of the stuff that you’ve seen is the science behind it, and we’re finishing digesting that.
The indication is that reservoirs will fill up earlier in the winter, which is a good thing because that’s when energy demand is at its highest, said Smith. The increase in spring precipitation means reservoirs could fill up higher in the future.
Still, the actual impacts are going to harder to measure. Additionally, heavier rain events in the spring could put sudden pressures on reservoirs, which are managed both for power generation and flood control.
“We have to forecast weather and hydrology now, and that’s going to be more unpredictable, I think, in the future,” she said. “That’s going to make it harder for us to forecast with accuracy going forward, so that’s going to impact how we plan. We might have to put more of a buffer around our operational plans.
“I think it’s going to be more challenging to operate in the future.”