Friday, 19 August 2016

When all HAIL breaks loose

Is it just me, or is there more hail than usual?

If you live in the Calgary, Airdrie, Red Deer, and the Sylvan lake area, it may seem that every single afternoon there are thunderstorms and hail warnings. Although we live in what scientist refer to as “hailstorm alley,” that is, an area that is a hot spot for forming clouds that cause these pesky hailstones to smash down on us, we are seeing a lot more hail than usual this summer.

We all know hail can wreak havoc on homes and vehicles, but did you know that insurance companies have spent over 2 billion dollars in Alberta hail insurance claims in the past five years?! Hail can also cause serious damage to crops, which can greatly affect the livelihood of farmers. So what are we doing about? 

We can purposely change the weather.  No really, we can do that:

Unbeknownst to many people, weather modification is actually a thing that is researched and implemented in many countries around the world. Mostly, weather modification is done to help moderate storms such as hurricanes and hailstorms, but also to help increase precipitation.

In 2008, China launched over 1,000 silver iodide rockets into the sky to ensure all the clouds dropped their rain before they reached the opening ceremony arena.

Alberta Hail fighters:

While we keep our eyes to the sky, and our weather alerts on during potential hail days, a team of scientists, meteorologist, and pilots work 24-7 in Didsbury Alberta to help minimize the damage of hail to our homes and vehicles.  Completely funded by private insurance companies, this team of 15 operate tirelessly form June to September monitoring weather patterns for hail risk. Without this team, we would definitely see larger hailstones and more hailstones showering down at us, causing millions upon millions of damage. So how do they do it? How do they change the weather to minimize the amount of hail we get? They use technique called cloud seeding.

We fertilize clouds?

Not exactly, but in Alberta we use a cloud seeding technique that involves twin engine planes flying into thunderstorm clouds and injecting billions of microscopic silver iodide particles. Can you imagine flying a tiny plane into a thunderstorm cloud? Here’s how these particles mitigate hail damage:

Hail is produced through strong to severe thunderstorm clouds which create really fast currents of upward moving air, referred to as updrafts. These updrafts are strong enough to push dust particles and water droplets to freezing temperatures. The water droplets form around the dust particles, bonding together and attracting more and more water particles. It takes 20-40 minutes to produce hailstones. Once the hail is heavy enough, they drop to the ground.

Hail stones measuring 5 cm in diameter. You can see the nucleus in the hailstone on the right

By injecting the silver iodide particles into the hail producing clouds, the tiny silver particles compete with the dust particles for moisture. What this does is prevent hailstones from growing too large.
Essentially, cloud seeding doesn’t take away hail; it just makes the hail much smaller, and less likely to damage your property.

Silver Iodide Flares that are directly injected into cumulonimbus clouds

So the next time you see that massive dark cloud in the sky (you know the one: it’s that cloud that looks like it’s reaching up to the sky, ready to unleash hail’s fury at you), remember that there are brave pilots up there, trying to save you a lot of time, stress, injury and money.