September 25, 2020

Fascinating, Unprecedented, Frightening flooding in North America

  • Vancouver Island Inland Sections Forecast - No watches or warnings in effect.

    Forecast Issued 4:00 PM PDT Thursday 24 September 2020 - Thursday night: Cloudy with 60 percent chance of showers this evening. Rain at times heavy beginning late this evening. Risk of a thunderstorm early this evening. Amount 20 to 30 mm. Wind becoming southwest 40 to 60 km/h before morning. Low 13. Friday: Rain ending in the morning then mainly cloudy with 40 percent chance of showers. Wind southwest 40 to 60 km/h diminishing to 30 in the morning. High 18. UV index 3 or moderate. Friday night: Mainly cloudy with 40 percent chance of showers. Low 10. Saturday: Cloudy with 60 percent chance of showers. High 17. Saturday night: Showers. Low 11. Sunday: Periods of rain. High 15. Sunday night: Periods of rain. Low 11. Monday: A mix of sun and cloud. High 23. Monday night: Clear. Low 10. Tuesday: Sunny. High 23. Tuesday night: Clear. Low 10. Wednesday: Sunny. High 22.

The great plains of North America are currently experiencing the greatest flooding in 150 to 300 years.

CBC and CNN are both carrying footage live.

Today the Province of Manitoba intentionally breached a dyke on the Assiniboine River, flooding hundreds of houses and thousands of square km of land to protect against an uncontrolled breach that would threaten whole towns.

Assiniboine Breach
Picture from CBC News website of breach as it started flowing this morning.

The flow of the Assiniboine is currently 1/2 the rate of Niagara Falls.

Incredibly, at opposite ends of the central North America flood plain, the situation is even worse.
North America water basins

At 1PM today, the US Army Corps of Engineers will take the unprecedented step of having all 3 Mississippi flood diversion structures active at once when they open the Morganza Spillway. It will flood 2500 homes and threaten thousands more.

This is being done to protect the “Old River Control Structure” which keeps the Mississippi flowing through New Orleans and keep it from threatening millions in New Orleans and Baton Rouge and keeps that key economic centre of the US economy afloat, literally.

Old River Control Structure
The Old River Control Structure a couple days ago.

Why is all this happening? Major and persistent snowfall over the winter thanks to La Nina and big rains this spring. Global Warming could play a role as well as a warmer atmosphere will harbour more moisture and that moisture, whether snow or rain, ends up somewhere.

Morganza Spill Structure in 1973
Morganza Spill Structure the last time in 1973

Today, it is ending up, in incredibly dramatic ways, in Lake Manitoba and the Gulf of Mexico.

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Back home here, we can expect more rain over the weekend. Get out and about while you can. Late next week we should warm up a little.

1 thought on “Fascinating, Unprecedented, Frightening flooding in North America

  1. Wow, while it seems Manitoba has escaped the worst-case scenario, the fires in Alberta are wreaking havoc.  We sometimes need to just consider how fortunate we are.
    In fact, the EC forecast is now full of shiny yellow balls for the upcoming long weekend!  Could we hit 20C by Thursday? 

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