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:
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.
A massive fire broke out after an explosion at the GE's Appliance Park in Louisville, Kentucky April 3, 2015. Was it weather-related?
The Ambient WeatherBridge is a breakthough in electronic weather station Internet transmission.
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.
This year had been a markedly (and thankfully) slow year for tornadoes. That luck ran out last night, when multiple twisters struck Oklahoma and Arkansas.
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.
Super Cyclone Pam, at Category 5 Hurricane strength, is razing the island nation of Vanuatu today. How does it compare to historical storms there?