Tracking severe weather in the Highlands
By Jenn Watt
Published May 15, 2018
Severe summer weather can arrive with little warning, destroying property, downing trees and sometimes threatening lives.
Environment Canada has plenty of methods of tracking storms as they develop, but they can’t always get on-the-ground information leading up to and following a severe weather event.
To help them gather information and to better warn other communities of coming danger, a network of 7,000 volunteer CANWARN weather spotters have been trained across the country.
They report large or extensive hail, heavy rain, damaging wind, funnel clouds, waterspouts and tornadoes.
On Saturday, a new crop of volunteers gathered at Bark Lake Leadership and Conference Centre near Irondale to learn how to spot severe weather from Geoff Coulson, warning preparedness meteorologist for Environment Canada.
“CANWARN spotters are letting us know, have they had flash flooding? Have they had tree damage from downburst winds? Have they seen a funnel cloud or a tornado… all of this information key to help the forecaster better understand the significance of the storm,” Coulson said.
“CANWARN spotters are helping us to ground-truth what we’re getting from radars, lightning detection network and satellites. Many of our Ontario tornadoes are weak and difficult to detect and so again timely reports from trusted sources on the ground are important.”
In order to prepare the volunteers for what they might see, the meteorologist instructed them on how to identify types of thunderstorms, the difference between a downburst and a tornado and to be cautious about misidentifying a false funnel as a tornado or funnel cloud.
Terry Moore of Environment Haliburton, which co-sponsored the event with Bark Lake and Canoe FM, told the audience that learning these skills is one way to build resilience in the community as it grapples with the effects of climate change.
“We’ve had two 100-year storms, floods, in the last four years in Minden and in large parts of the county. We know the changes climate change is bringing are already here,” Moore said.
“What we wanted to do was ... help give people both an advance warning if there’s extreme weather coming their way, but also to help Environment Canada ground-truth what exactly happened on the shores of Kashagawigamog, anyway? Was this a downburst? Was this a tornado? What exactly did occur here?”
Most people now have smartphones with them wherever they go, which means reporting of bad weather is far more common than it once was, however, Coulson said that doesn’t necessarily help scientists.
“Social media is also giving me reports like ‘boy is the sky dark’ and ‘yeah, that’s a lot of lightning,’” he said.
For example, while someone might think they see a tornado on the horizon, sometimes it will be strangely shaped clouds. The telltale sign is swirling debris on the ground beneath that funnel shape.
Environment Canada puts out four different alerts – special weather statements, advisories, watches and warnings.
The last two would be used to prepare people that a storm is on its way. Watches are for larger geographic areas and talk about the potential for a severe storm to develop. The warning is for a smaller area and is more time sensitive.
“One of the challenges we face with severe weather is the speed with which these storms … develop and move. That means the average lead time for many of our severe thunderstorm warnings and tornado warnings is minutes, maybe 10 to 15 minutes on average before that weather arrives at your location,” Coulson said.
While summer warnings come quickly, in the winter, the storms are larger and easier to track ahead of time.
For a storm to be severe, it needs to have any or all of the following features: big hail the size of a nickel or larger; heavy rainfall – for example, a month’s worth in one storm; damaging bursts of wind with speeds of more than 90 kilometres an hour; produce one or more tornadoes.
Coulson said most Ontario storms will produce one or two of the above features, but that “super cell” storms can bring all four.
Coulson taught the group to identify the difference between single cell, multi-cell cluster and super cell storms.
His talk was also peppered with frequent warnings to be safe when spotting storms.
Lightning can travel distances of up to 17 km all around the storm, which means the sky above could be blue in Ingoldsby and lightning from a storm above Minden could still strike.
One of the best online tools for tracking incoming thunderstorms is a German-based site called www.lightningmaps.org. It uses lightning censors from around the world to track activity in real time.
Thunderstorms need three ingredients to form, Coulson said.
First, there needs to be a supply of low-level moisture, which he called the fuel. For this region, that frequently comes from the Gulf of Mexico. Second, unstable air. Third, something to kick it off creating lift, which could be a cold front or it could come from lake breezes in the case of the Great Lakes.
Coulson also talked about downbursts, which he said were often confused with tornadoes since tornadoes take up so much of the popular imagination.
“These bursts of wind often have widths of damage significantly wider than tornadoes, often have wind speeds that rival most of the tornadoes that we get in Ontario,” he said.
“Unfortunately, until the Discovery Channel has a show called Downburst Chaser, I’ll spend the rest of what’s left of my career trying to convince folks of the significance of these events,” he said. (Coulson told the group that it’s a matter of months before his retirement.)
Downbursts are gusts of wind that come down out of a storm.
“If the storm is stationary and the burst of wind comes out and hits the ground, it spreads out in all directions. If we look at the damage from above, it looks like a starburst,” he said.
When the storm is moving, all of the debris will be laid in one direction.
This can help investigators who arrive after the storm determine if it was a tornado or downburst.
Since the role of CANWARN storm spotters is ultimately to improve safety for everyone, Coulson dedicated time to talk about safety during extreme weather events.
Lightning takes the shortest path to the ground, he told the audience, striking trees, chimneys, hilltops. When you hear thunder, go inside and stay inside until 30 minutes after the last rumble of thunder (keep in mind, lightning can travel 17 km).
Seek the best shelter. Go to the basement. Stay away from windows, doors and plumbing. Do not use the landline. If you only have your vehicle, that is better than being outside.
“No place outside is safe during a thunderstorm,” he said. However, the vehicle should have a metal roof. “It’s the metal cage of the vehicle that gives us lightning protection, not the rubber tires.”
When on the water, as soon as you hear the first rumble, you should get to shore and then from there get to shelter.
People in the audience asked what to do if you’re camping somewhere without a shelter and without a car, like backpacking or canoe camping in Algonquin Park.
“Everything is better than a tent,” he said.
While it may be human nature to stay within the shelter of the tent, it will not protect you from flying debris. If there is a structure, go there. Cabins and cottages are best.
If there is a vehicle, use that, but make sure it’s not under any large trees that could fall on it.
Park the car away from objects that could hit the car.
If you have no shelter at all, the best thing to do is go to a low-lying area, lie flat and cover your head, he said. Even that is no guarantee of safety.
The best defence is to be prepared, have a plan and watch the weather forecast.