Before all memory of it slumps into the torrent and is washed away downstream, I want to comment on the aftermath of the rainstorm that stalled over Southern British Columbia on November 15th, 2021.
Two weeks on from that singular event, media have been filled with stories about the unprecedented flooding and destruction caused by the meteorological phenomenon commonly known as “The Pineapple Express” now more solemnly and correctly referred to as an “Atmospheric River”.
Just over two weeks’ ago, as is expected most every year, an airborne river of warm, moist, equatorial air rolled up from the South Pacific ocean two weeks ago and flowed Northeast toward to the North America.
As the mass of air moved inland over rising terrain, it slowed, and the enormous volume of air rose and cooled which caused dissolved water vapour to change into liquid water and to fall as rain.
To some casual observers it seemed to stall completely, blocked by the physical barrier of the Coast Mountains.
In October and November, residents of South Eastern British Columbia expect the weather to turn increasingly dark and unsettled. Wind storms with heavy lashing rain and its effects: falling branches and trees, super-saturated soil, wash-outs, and flooding. But the almost stationary weather system that parked over British Columbia on November 15th, 2021 was unprecedented in the amount of precipitation it delivered to inland areas of British Columbia, particularly in the Eastern Fraser Valley and beyond up and through the rising, mountainous valleys of the Fraser, Coquihalla, Coldwater, Nicola, Tulameen and Similkameen Rivers and their tributaries.
Channels of fast-moving, warm, moist air moving inland slow down a lot and as the increasing altitude of the land forces the air above to rise. Rising air cools; cool air is unable to hold as much water vapour as warm air, so it condenses and falls as rain. Think of a water-filled sponge being forced into an opening that is just a little too small to receive it. The sponge will be squeezed through the opening, but it will give up a lot of the water it is holding in the process. That is what happened in Southern British Columbia on November 15th.
I don’t want this to turn into a trite lesson on what happens when a month’s worth of precipitation falls in less than a day, (which is what happened in Southern British Columbia on November 15th, 2021); instead, want to focus on a single fact: It was a single weather-event caused a long string of negative, consequential events which continue to play-out, now two weeks on from the singular event.
For now, I’d like to mention just one of these.
As a result of the precipitation that fell over Southern British Columbia on November 15th, ALL but one of the main, East-West highways in British Columbia were shut down. They were either completely inundated by flood waters, overwhelmed by mud and debris flows, undermined by rushing water, or as in the case of at least one secondary highway, completely washed away.
I will not editorialize here except to say that such devastation across such a wide area does not usually happen to a country except in a time of total war.
As far as I can tell, British Columbians are not ‘at war’ with anyone, except perhaps themselves, so in that sense we’ve gotten off lucky.
Two weeks’ after the event, due to an effective response from federal, provincial and local governments, further catastrophic damage to infrastructure has been avoided. Some damage has been restored, (dikes have been patched up), sand-bags have been laid to protect residential sub-divisions built on flood-plains, and heavy equipment has been tasked with clearing a path through the muck and debris.
The job of rebuilding the highways and bridges that have been lost will take longer, but even that work seems to be proceeding well enough; as best as can be expected under the current circumstances, come what may.
What has over the past 50 years or so has been a never-ending train of highway transport trucks delivering all kinds of goods from places far away was suddenly blocked for a number of days.
Now, two weeks’ later, some of these transport trucks, semi-trailers and B-trains, (those that did not back-up, turn-around and head back from whence they came) are once again inching their way forward, in much the same way as water does when it starts to accumulate and back up on flat, level ground.
In a future blog-post, I’d like to comment on some of the, dare I say ‘downstream’ effects of the atmospheric disaster of November 15th, because I have a sense that there may be a lot more to capture our attention in the days and weeks to come.
The Crowsnest Alliance 