Source: Strang Sounds
Another atmospheric river is about to slam into western Washington and parts of British Columbia, Canada, for the third time in just under a week on Tuesday-Wednesday.
Here comes the third atmospheric river in just under a week that will once again give rain heavy at times over the BC south coast. Heavy rain may ease somewhat Tuesday night but will persist through Wednesday as a cold front moves across the region. #Goes17 #BCStorm pic.twitter.com/x6ryC0WQrX— Jason Ross (@Squamishweather) November 30, 2021
Rivers in the sky have led to landslides blocking roads, rivers inundating towns, and in one case, returning an old lake bed back into a lake.
The new monster storm is about 8,000km long
Astounding view from space of a several thousand mile-long atmospheric river being pushed across the North Pacific into British Columbia by an exceptionally strong Pacific jet extension. #BCstorm #BCflood pic.twitter.com/lRSItbdwk0— US StormWatch (@US_Stormwatch) November 30, 2021
British Columbia typically sees atmospheric river events in the month of November, just as the Pacific Northwest does. The problem for both regions this year has been the consistency of the systems, with no breaks for drying in between.
“The first atmospheric river event hit us hard on November 13 to 16, and it dumped a lot, 150-300 mm (roughly 6 to 11 inches), of precipitation in less than 48 hours,” Johnson Zhong, a meteorologist for Environment Canada said.
Updated November monthly averages and rainfall totals so far this month across #BC cities, majorly from the multiple rounds of #AtmosphericRiver events. More to come, 100-200+ through Wednesday for Tofino and Hope, who have already seen over 600mm #BCStorm #BCFlood #BCwx pic.twitter.com/TnjIUQtXMz— Rachel Modestino TWN (@ThatMetGirl) November 29, 2021
There has also been rain on top of fresh snow, which has exacerbated flooding.
“There was up to 30-50 cm (1-1.5 feet) of fresh snow at 1500-2500 meters (5,000-8,000 feet) high,” he observed. “One of our atmospheric river events rained much higher than 2500 meters, so that rain melted the snow and helped create the flooding.”
New Lake in Suma
One of the areas seeing the greatest amount of flooding was the Sumas area, about 50 miles east of Vancouver.
“One hundred years ago there was a Sumas lake. Then they pumped the water out to make good farmland. It has been farmland for the last 100 years, and now it’s a lake again,” Zhong explained.
What is Sumas Lake? 100 years ago, Abbotsford had a 134 sq km lake. So why are we say climate change caused this flooding in BC? Do not build in a lake bed. https://t.co/3TqkM84KvX— Rob (@RobYEG) November 28, 2021
The unprecedented amount of rain has created major flooding, washing out bridges and roads, completely cutting off many other small Canadian towns to the rest of the world.
Merritt, British Columbia, is one of those towns.
“Merritt is a town of 7,000 people and is totally flooded,” Zhong said. “That town is in an area that doesn’t get a lot of rain. But with the combination of rain and snowmelt, the entire town flooded. The water and sewage system went down, and the entire town had to be evacuated.”
Third atmospheric river in a row
Now the third wave is coming. Environment Canada says up to 200 millimeters of rain could drench the central coast of B.C. and parts of Vancouver Island through Wednesday, possibly causing water to pool on roads and flooding in low-lying areas.
Another potent Category 4 atmospheric river tapping into tropical moisture is headed for waterlogged British Columbia and the Pacific Northwest and is expected to bring additional heavy rainfall and flooding. #WAwx #BCstorm #BCflood pic.twitter.com/qYf9eijtUa— US StormWatch (@US_Stormwatch) November 30, 2021