Storm Hunter Mark Robinson says tornadoes aren't always easy to find and are often identified after they are gone. A damage survey team from Environment Canada heads to the scene to determine the severity of the storm.
“The idea is to come out and gather all of the characteristics of a particular event,” explains Research Scientist Dave Sills with Environment Canada. “But a lot of times all we have is a report of damage and we come in and determine whether it's a tornado or a downburst.
Sills adds that during a lot severe weather events they receive reports of funnel clouds, but without a location of where the damage may be, it makes it difficult to assess and compose a damage survey.
“When I started doing these damage surveys I was very keen on going out, but you're basically going on a wild goose chase because you have nowhere to look.”
Another challenge that the survey teams face is the involvement with members of the affected community.
“In cases like the Goderich tornado, communities start to rally and they come on scene and they start to help out and for all the good intentions they start moving debris and cleaning up the mess,” says Environment Canada meteorologist Randy Mawson. “But that mess of course, that's all forensic information for us and tells us exactly what happened and how things unfolded.”
Survey teams try to get to the scene as soon as possible to investigate the mess before anything is cleaned up. They “criss-cross” the damage areas they know about and go as far they can.
“And when we find areas that don't have damage, we've hit the extent of the tornado,” explains Sills.
Based on the look and direction of damage, survey teams are able to conclude the type of severe weather generated. Investigators will usually deduce the damage to either tornadic activity or straight-line winds.
Find out more on how experts tell the difference between straight-line winds and tornadoes. You can also learn more about measuring the damage on intensity scales.
With files from Andrea Stockton