Saturday, October 18, 2014

Gonzalo's Storm Surge Inundation Reached at least 6 ft (~ 2m)

Hurricane Gonzalo's storm surge did not cause as much damage as feared, although the surge did damage boats and low-lying infrastructure. The highest storm tide inundation I could find occurred at L.F. Wade International Airport, where AWOS weather sensors were, "damaged due to saltwater inundation" (Stewart 2014). The elevation of the airport is 6 ft (~ 2 m), which means a combined storm tide + waves reached at least this elevation to damage these instruments. (Airport information available at: http://bermuda-online.org/airport.htm).

A combination of storm tide and waves damaged AWOS weather sensors at L.F. Wade International Airport, where the elevation is 6 ft (~ 2m).
Map: Wikipedia Commons, Graphics: Hal Needham

Bernews posted numerous storm damage photos, some of which show boats washed up on shore. The positioning of the boats suggests the surge in these locations was at least several feet (~ 1 m) high.

Gonzalo's storm surge washed small vessels onshore


Gonzalo's storm surge washed small vessels onshore



This morning, Jim Edds posted photos of damaged causeway sections. Apparently, Gonzalo knocked down six concrete wall sections of the causeway, however, it is not apparent if water or strong winds toppled these sections. Most online photos today suggest that wind damage was more severe than surge/ wave damage.

It should be noted that waves outside the reefs were much higher than storm surge/ storm surge heights inside the reef. As Gonzalo approached Bermuda, seas (open ocean waves) were forecast to exceed 30 ft (9.1 m).

 Photo of causeway damage from Jim Edds (@ExtremeStorms) 
Photo: https://twitter.com/ExtremeStorms


Please feel free to send me any surge pics or observations! My email is  hal"at"srcc.lsu.edu.

Thanks!
Hurricane Hal

REFERENCES

Stewart, 2014: Hurricane Gonzalo Discussion Number 23. 1100PM AST FRI OCT 17 2014. Available on the Web at: http://www.nhc.noaa.gov/archive/2014/al08/al082014.discus.023.shtml?.

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