Bombogenesis aka Bomb Cyclone

[gavinski91]

the pseudo floodplain manager in me is curious if these flooded areas were in the FIRM-mapped (or USACE mapped) 1% (100-year) or 0.2% ( 500-year) floodplain. any known failures to floodplain structures such as levees or floodwalls?

A bit of a mixed bag. Some of the areas inundated were in the FIRM 1% flood area, but some were outside of it. Additionally some places that are in the 1% area stayed dry. https://www.whatcomcounty.us/Documen...eas-PDF?bidId=
I know of two levee failures during the flooding, but neither contributed significantly to the flooding. One was a small creek that failed outside of the 100-year flood area but only impacted a few homes, and another was a levee failure on the Nooksack that occurred in the floodway after the peak of the flooding.
Sediment levels in the river have risen significantly since that map was last updated though, and no work has been permitted to remove any of it. Perhaps this flood will change that.

[LongShortLong]

What a mess. I watched an older video where a hydrologist said the design flood (500 year) for Fraser River is something near 60,000 m^3/s. From poking around at various river gauges, the highest I could find for this flood is 6,000 m^3/s. Anyone know what's up with that? I suppose it does look like the normal 100-year flood aftermath in California - some area near a river covered in brown water, ag land or former ag land.

Hope you all dry out soon.

[bodywhomper]

A bit of a mixed bag. Some of the areas inundated were in the FIRM 1% flood area, but some were outside of it. Additionally some places that are in the 1% area stayed dry. https://www.whatcomcounty.us/Documen...eas-PDF?bidId=
I know of two levee failures during the flooding, but neither contributed significantly to the flooding. One was a small creek that failed outside of the 100-year flood area but only impacted a few homes, and another was a levee failure on the Nooksack that occurred in the floodway after the peak of the flooding.
Sediment levels in the river have risen significantly since that map was last updated though, and no work has been permitted to remove any of it. Perhaps this flood will change that.

Thanks for the info. A lot is going to be different now.

[Ted Striker]

Nooksack River



Flood water floating on salt water in Hale Passage