Jesse Ferrell

Share |

Galloping Calgary: Canadian Road Sign vs. Wind

August 21, 2012; 11:48 AM ET

UPDATE: Thanks to a commenter, here is an article with more videos from this thunderstorm.

This YouTube video showed up in my mailbox this morning, as a "Top 5 Most Viewed" video, and it now has over one million views:

INCREDIBLE FOOTAGE Sign blowing around on Deerfoot

I did some research (for our news story) to determine what wind conditions caused this incredible event. On Aug. 14, winds were sustained as high was 41 mph gusting to as high as 60 mph from the north-northwest during a thunderstorm between 2:45 and 4:00 p.m. local time at both Calgary International (graphed below) and Calgary/Springbank airports:

According to Google Maps & Street View, the location of the driver would have had a north-northwest wind behind him, which meant it was blowing perpendicular to the street sign's horizontal support bar -- not unlike what happened when winds perpendicular to the Tacoma Narrows bridge ("Galloping Gertie") caused it to crash in 1940 (except then it caused twisting, not simple bouncing up and down). This is my guess anyway, I'm by no means an expert on Aerostatic Fluttering; if you are, leave me a comment below. One YouTube commenter said that the bad engineering of signs spanning too many lanes contributed to the problem.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

Comments

Comments left here should adhere to the AccuWeather.com Community Guidelines. Profanity, personal attacks, and spam will not be tolerated.

More The WeatherMatrix Blog

  • Pennsylvania Triple Shelf Cloud, Mothership

    March 27, 2015; 3:50 PM ET

    Eastern Pennsylvania was darkened by a massive, triple-decker shelf cloud last night. It was the first thunderstorm of the year, and it did not disappoint.

  • Frozen Susquehanna River Turns to Ice Jams

    March 21, 2015; 1:51 PM ET

    After a few warm days, the ice was on the move, in some cases causing damage. Here are photos and videos from the Pennsylvania Storm Chasers.

  • Category 5 Cyclone Pam Vs. Vanuatu History

    March 14, 2015; 2:19 PM ET

    Super Cyclone Pam, at Category 5 Hurricane strength, is razing the island nation of Vanuatu today. How does it compare to historical storms there?

About This Blog

Jesse Ferrell
Jesse Ferrell's WeatherMatrix blog covers extreme weather worldwide with a concentration on weather photos and Social Media.