Extremely cold temperatures have dominated the forecast for the past week and have caused some interesting phenomena to occur in the atmosphere. Environment and Climate Change Canada Meteorologist, Stephen Berg, says the cold is directly responsible for the appearance of sun dogs and light pillars in the sky.
“They're usually seen in cold weather conditions, as we've been having for the last little while. It happens when sunlight scatters off of ice crystals. So, it's just the directional scattering of sunlight off of these ice crystals, largely high in the atmosphere.”
“Sun dogs” refer to a bright spot appearing on one or both sides of the sun, while light pillars refer to a beam of light appearing to extend vertically above or below its source. Outside the temperature, it indicates other conditions present in the atmosphere.
“There's a decent quantity of ice crystals. That might mean that you might see some cirrus clouds and sort of higher clouds, less near-surface clouds. It would be just an indication that most of the atmosphere above is full of ice crystals rather than supercooled water droplets. Water droplets can stay present in the atmosphere even at temperatures colder than minus 30, but they're far less abundant at those temperatures than they are at minus 10, minus 8, something like that.”
There’s a common belief that sun dogs indicate an incoming change in weather conditions, Berg says he’s unaware of its scientific merit, but in this case, it may be true as temperatures are expected to warm up by the end of the week.
Regardless of a potential change, Berg notes the importance of dressing warmly as the cold snap persists and being prepared for the winter weather.
“Make sure you're spending as little time as possible outside and make sure you have survival kits in your vehicle for if you're out and about on the roads, especially if you're out on the highway, if your car breaks down, that'll be not so good. So, stay warm and stay safe.”