THE ERA OF WEATHER EXTREMES IS UPON US: “Ecology is not rocket science. It’s way more complicated. This is not to downplay the difficulty of rocket science, but to point out the incredible complexity of natural systems where all the variables aren’t known and are often connected to and influence one another,” stated Armel Castellan, meteorologist with Environment and Climate Change Canada (December 2021)

Note to Reader:

Record-breaking precipitation in November 2021 drenched British Columbia, a striking contrast to the hot and dry days of summer when several cities were evacuated due to wildfires. This focused attention on the work of meteorologists with Environment and Climate Change Canada (ECCC) in providing early warning of extreme weather events. Armel Castellan, Warning Preparedness Meteorologist, has emerged as the face of ECCC in conducting media interviews.

B.C.’s year of extreme weather ‘consistent’ with climate change

On November 30, 2021, ECCC took the unusual step of holding a media technical briefing regarding upcoming severe weather in British Columbia.

“British Columbia finds itself in the throes of the wettest fall on record for many stations across the South Coast, including Vancouver International Airport, Abbotsford, Victoria, and Nanaimo. This has been a very active streak since mid September on the heels of an extremely dry and hot summer. Each storm may not be as bad but the overall trends will be towards more extreme weather,” stated Armel Castellan. His job is to translate complex forecasts into a language people can understand.

“In 2017, we turned a pretty big corner, That year was a strong wildfire year. In fact, it was record-breaking at the time, only to be outdone in 2018 by (total) hectares burned.”

“We know that the ecosystem is ultimately connected, and one thing has an impact on another, and we don’t have to look too much deeper than just this past summer (2021). In fact, three of the last five summers, with extreme wildfire behaviour and knowing how drought and wildfire burn scars have an impact on the landscape and can be manifested in the wet season a few months later.”

British Columbia’s first “Red Alert”

On November 27, 2021, Environment Canada had issued its first “red alert” for British Columbia ahead of what officials were characterizing as a dangerous weather system expected to push more atmospheric rivers into the province. “The red level is something new that we have not issued,” stated Armel Castellan.

“Storms are coming back-to-back-to-back with very little time in between. So, imagine that we’ve had an extraordinarily wet fall, the landscape is completely saturated. Any extra moisture runs down much more easily and quicker,”

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Adjusting to a Changing Water Cycle in British Columbia: Longer, drier summers & warmer, wetter winters

On the weekend of November 13-14, 2021 the southwest corner of British Columbia was pounded by an epic atmospheric river. Landslides and rampaging rivers severed all highway connections between the Lower Mainland and the Interior of the province.

Barely 48 hours later (on November 17, 2021), the Partnership for Water Sustainability’s Kim Stephens delivered the keynote address at an operator educational event organized by the BC Water & Waste Association (BCWWA). Held in New Westminster, the BCWWA event was distinguished by the fact that it was not a Zoom webinar.

On the contrary, it was the first in-person event for water education in the age of COVID. Thus, it was an ironic twist that Mother Nature prevented speakers and attendees from the Interior from attending. The rippling impact of the natural disaster was further accentuated when some 20 municipal staff from the cities of Abbotsford and Chilliwack were called to duty. It was all hands on deck in those communities after widespread flooding in Sumas Prairie shutdown the Trans Canada Highway.

In summary, the historic storm and flooding was top of mind for all when Kim Stephens, Partnership Executive Director, stepped on stage to provide his career perspective on current events, and put the situation in context.

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Download a copy of the keynote presentation titled Adjusting to Longer and Drier Summers in British Columbia:  Drought Affects Us All.

A Career Perspective on Droughts and Floods in British Columbia

“Dating back to the Halloween 1981 Flood, my engineering career has been defined by an alternating cycle of floods and droughts. This four decade history provides me with perspective that in turn allows me to put current events in context,” stated Kim Stephens.

“In water resource engineering, we often talk about the Hydro-illogical CycleThat means – once a decade you have a flood; once a decade you have a drought. You write a report. You put it on the shelf. A decade later, you have a flood, you have a drought, you update the reports. And so the cycle continues. As the hist0ric storm of November 2021 shows, however, no longer can we postpone action that recognizes the nature and reality of a changing water cycle.”

“Droughts affect all of us, whereas floods affect some of us. That is a fundamental distinction. For this reason, drought history is a good way to tell the story of how our climate is changing. In British Columbia, the mega-drought of 1987 was our first wake-up call. It followed a relatively benign period of some four decades. In rapid succession, we had three droughts in five years. This began to change the conversation in British Columbia.”

“Starting in 2003, we have had one teachable year after another in British Columbia. The pattern has been extremes followed by extremes: droughts, forest fires, wind storms, and floods. Each time the extremes seem to be more extreme. 2015 is a defining year. With hindsight, we can clearly see that is the year when we crossed an invisible threshold into a different hydro-meteorological regime in western North America. We are now in Year Seven of this new reality. Yet only in 2021 is in finally sinking in with the population at large that something has fundamentally changed.”

“As of 2021, we can truly say that the era of weather extremes is upon. And it has happened faster than anyone had projected or expected. Think of the terms that are now part of the everyday vocabulary in weather forecasts on the evening news: heat dome, atmospheric river, cyclone bomb.”

Extremes are More Extreme

“We have always had weather extremes in British Columbia. In my experience, dry months would follow wet months. In other words, the duration of wet and dry periods was comparatively short. On an annual basis, things had a way of balancing out. Now, however, winters are warmer and wetter. And summers are longer and drier. This new reality has huge consequences for water security, sustainability, and resiliency.”

“A generation ago, for example, water supply managers could reasonably anticipate that three months of water storage would be sufficient to maintain supply during a dry summer. Today, however, a 6-month drought is a very real likelihood, and on a repeating basis. In the meantime, populations have also grown in the major centres. From a water supply perspective, think about the implications of a doubling in the need for water storage to make it through a drought.”

“When the water resource is large and water demand is small, variability is not that noticeable. But when the demand (Water OUT) is large relative to the available resource, a variation on the supply side (Water IN) magnifies the perception of impact. In many cases, BC communities have long been operating on narrow margins.”

“When you think about it, the planet Earth is a closed loop system. Mother Nature does not create new water.  The state may change – rain, snow, ice, vapour – but the water cycle is the water cycle. This means that extreme duration dry periods will of course will be followed by extreme duration wet periods. And that has been the pattern since 2015, with 2021 being the most extreme year of all as we have lurched from heat dome to epic atmospheric rivers.”

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Learn From and Build Upon Experience

“A key message is that climate change is not a driver; rather, it is another variable. Climate change is only one factor to consider when we talk about the nature and consequences of extreme weather. The real issues are uncertainty and risk, more specifically how we deal with the first and manage the latter.”

“At the same time, we must recognize that we have so transformed the landscape that there are compounding unintended consequences. These are due to our widespread interference with natural processes. In November 2021, there were numerous factors in play and these combined to magnify the impacts of extreme weather.”

“In particular, the  epic atmospheric river covered such a large area extending into the Interior that it resulted in a previously unimaginable scenario – a major storm coincident with high water levels in the Fraser River late in the year. In the lower Fraser Valley, this meant that inland drainage could not outflow by gravity through the dyke system and into the Fraser River. Normally the Fraser peaks in the late spring and early summer months due to snowmelt, not rainfall.”

“Another key message is that everything is connected. This requires an understanding of how the system works as a whole, rather than focusing on components in isolation of the whole. Thus, a constant challenge for planning is not to prevent past events, but instead is to use past experiences and apply systems thinking to inform and create flexible strategies for the present and the future,” concluded Kim Stephens.

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