• MEGAN EVANS – January 25, 2018: The Buzz About Native Bees
• CORRIE TURNER – January 28, 2018: Winter Ecology and Wildlife Survival
• CHRISTIAN STENNER – February 15, 2018: Part 1 – The Caves of Kananaskis and Beyond
• ROBYN MULLIGAN – February 25, 2018: Nature-Inspired Art Workshop
• CHRISTIAN STENNER – March 9, 2018: Part 2 – The Caves of Kananaskis and Beyond (at the Rat’s Nest Cave)
• JOHN PACZKOWSKI – March 15, 2018: Wolverine Populations in South-Central Alberta 
• CHRISTIAN STENNER – March 23, 2018: Part 2 – The Caves of Kananaskis and Beyond (at the Rat’s Nest Cave)
• JIM THORNE – March 25, 2018: Winter Survival and Shelter Building

Part 3 in a series by Derek Ryder, Director of Communications

In January, I started this series by helping you understand what the good and smart folks at Environment Canada are doing when they generate weather forecasts. I promised then to come back to talk about the issue of what you can see on weather radar.

EnvircCan’s weather radar serves many purposes, but it is primarily tuned for aviation. They look up, because that’s where planes are, not across, where you are. There is a company that looks across and cares a LOT about what hits the ground: Weather Modification Inc.

Alberta insurance companies contracted with WeatherMod starting in 1997. WeatherMod’s job: attempt to modify damaging weather events, notably hail storms, to reduce insurance claims. This is achieved by flying airplanes into storms that could produce hail, and seeding clouds with products like silver iodide or frozen CO2 pellets. The goal is to make more precipitation droplets. This prevents just a few droplets from turning into BIG hail, and instead makes a ton of little hail that’s annoying but doesn’t break things like roofs, windshields or crops.

Hail’s a bit complex, but the way it forms is simple. Tiny drops of water condense on dust particles in the air. These fall and grow in size and would come down as rain, but are sucked back up by rising air in the thunderstorm. They rise through the freezing layer, freeze into pellets, then fall again when they get out of the rising air. That’s little hail. If they get sucked up again, they get bigger as more moisture condenses on them. Baseball sized hail has been up and down through the freezing layer dozens of times.

It’s tough to get your head around how fast air can be rising, both in and out of clouds. As a glider pilot, I was frequently in air rising upwards of 1,500’ per minute. It can get to 5,000’/min or more in a strong thunderstorm (that’s 100 km/hr). “Supercells” in the US have had air measured at 15,000’/min -- 300 km/hr. Hail and rain – even baseball sized hail – is always falling, but if the air it’s falling in is going up faster than it’s coming down… the hail goes up.

WeatherMod’s logic is to fill the sky with dust particles, which will make tons of little rain, that will become tons of little hail bits -- instead of letting just a few hail collect all the moisture and grow bigger. WeatherMod tunes their radar to look at what’s hitting the ground. They couple this wth EnviroCan’s radar that looks up, and they know where to send their cloud seeding planes.

For fun, in 2013, on a nice June afternoon with the sky full of thunderstorms, I grabbed sample images to look at the difference between the two radar images. I thought it would be a great day to show the difference between the weather radar image focused on air traffic that EnviroCan generates, versus the commercial weather radar image targeting forecasting ground precipitation and hail forecasting, from WeatherModification.

Here’s EnviroCan’s.


Here’s WeatherMod’s


Note they are a mere 2 minutes apart, so represent the same moment in time. WeatherMod’s pictures show info they need to suppress hail, such as cloud tops (in metres; that 11.4 sucker is a cloud 37,400’ tall), direction and speed (the red circles) so the display is busier; I turned on all the geographic reference features on the EnviroCan display, and clearly they offer better reference points than WeatherMod. But both show precipitation density on a colour scale.

Here’s some differences in the information they are showing:

All of this is also true in the winter. So when you skiers look at the EnviroCan radar image to see where it’s snowing, take it with a grain of salt. EnviroCan sees what they want to see, and what they want to see isn’t necessarily what skiers want to see.

The only downside to radar data is that it needs to be looked at in real time; this is why EnviroCan offers only 1 hr and 3 hr histories, and why WeatherMod just gives you the last 30 min. With limited cell coverage in K-Country, checking the radar may not be possible. Mostly, I look at it during storm events if I’m planning to go out the next day. It will tell me where got hit and will be wet and muddy with high running streams, and what escaped the blow, which helps in my day planning.