Another atmospheric river hits flood-stricken British Columbia, Canada
The third atmospheric river in the past 7 days is affecting British Columbia, Canada since early Tuesday morning (LT), November 30, 2021, bringing heavy rain and mountain snow.
Significant precipitation continues to overspread coastal and southern portions of British Columbia, as the last in a series of atmospheric rivers affects the region, The Weather Network (TWN) reports.1
A slew of rainfall warnings, snowfall warnings, and special weather statements are in effect as the moisture washes over the province.
The precipitation could lead to additional flooding, mudslides, and avalanches, potentially exacerbating an already precarious situation, TWN warns.
Widespread rainfall totals of 40 to 120 mm (1.6 to 4.7 inches) are expected by the end of the storm.
The highest totals are likely on western Vancouver Island and at higher elevations, where 100 – 200+ mm (3.9 – 7.9 inches) of rain is possible. Storm totals of 40 – 70 mm (1.6 – 2.7 inches) are possible around Metro Vancouver.
Image credit: NOAA/GOES-17, RAMMB/CIRA, TW. Acquired at 20:00 UTC on November 30, 2021
Environment Canada and Climate Change has issued special weather statements and rainfall warnings for the North, Central and South coasts, as well as the Lower Mainland.1
Snowfall warnings are in effect for Fort Nelson and the Yellowhead, while winter storm warnings are in effect for inland sections of the North Coast, including Stewart.
Runoff from snowmelt and a risk for avalanches will become a concern through Wednesday, December 1 as freezing levels quickly rise.
Continued snowmelt will further swell B.C.’s rivers, exacerbating the risk for flooding at lower elevations.
Evacuation orders remain in effect for properties near waterways in the Fraser Valley and in the Thompson-Nicola Regional District.2
The mayors of two Fraser Valley communities that have been hit hard by flooding this fall3, 4 say they are confident their residents can make it through these next two days of rain.
"I am pleased to share that at this point, we are holding our own," Mayor Henry Braun of Abbotsford said. "Unless we get a 200 mm [7.9 inches] dump Tuesday and Wednesday — that's a whole different ball game then," he said.
1 Heavy rain, high avalanche danger as atmospheric river washes over B.C. – The Weather Network
2 Storm brings another round of heavy rain to B.C.'s soaked southwest – CBC
3 Atmospheric river hits British Columbia, causing major floods and landslides, Canada – The Watchers
4 Agricultural disaster after record rains cause catastrophic floods in British Columbia, Canada – The Watchers
Featured image credit: NOAA/GOES-17, RAMMB/CIRA, TW. Acquired at 20:00 UTC on November 30, 2021
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Tsuga heterophylla, the western hemlock is native to this area because it is a natural temperate coastal rain-forest on the windward side of a coastal mountain range. A natural rain-forest experiencing rain. Highly unusual, so it must be anthropogenic global warming causing all this rain in a windward coastal mountain range rain-forest. What else could it be? A satellite image confirming why a windward coastal range rain-forest is a coastal range rain-forest and the source of rain for the coastal range rain-forest? Close to 25% of the world’s temperate rain-forest is in BC. This forest (referred to in British Columbia as the Coastal Western Hemlock biogeoclimatic – or BEC– zone) can thrive from sea level, close to the seashore, up to 900 m of elevation, where the subalpine (or the Mountain Hemlock BEC zone) forest begins. On the coast, humid winds caused by the warm oceanic currents cool down when they are forced upward by the Western Cordillera Mountains. This brings 1.5 to 3.5 m of rain every year, making British Columbia’s coastal temperate rain-forest amongst the wettest non-tropical areas in the world!
Bottom line. It rains on the West coast of British Colombia, a lot, naturally.
Note: the calculations for the amount of rainfall are all wrong.
100mm = 39.6 ins
200mm = 79 ins
(The decimal point is in the wrong place.)
1 inch = 2.54 cm = 25.4 mm.
3,9 inches * 25.4 mm/inch = 99.06 mm
7.9 inches * 25.4 mm/inch = 200.66 mm