CALGARY – Residents in and around Calgary spotted funnel clouds as early as 11:30 a.m. Sunday morning east of the city and in Calgary’s northeast.
Environment Canada has issued a weather advisory for the City of Calgary stating:
“Conditions will be favourable for the development of funnel clouds early this afternoon.These types of funnel clouds are generated by weak rotation under rapidly growing clouds or weak thunderstorms. This weak rotation is normally not a danger near the ground. However, there is a chance that this rotation could intensify and become a weak landspout tornado. If conditions become more favourable for the development of landspout tornadoes, watches and warnings will be issued by Environment Canada.”
“Landspout tornadoes do not usually cause significant damage but can still be dangerous. They can be strong enough to topple trees, damage roofs or toss debris short distances.”
Environment Canada says to treat any funnel cloud sighting seriously and if you see one nearby, take shelter. They usually appear with little or no warning.
Global Calgary weather anchor Jodi Hughes says what our city is seeing today is what’s called ‘Cold Core Funnel Clouds’.
“They are typically weaker, are usually harmless and rarely touch the ground. Cold core funnel clouds usually form behind a cold front when there is some instability in the air,” Hughes said. “Basically it works like this: you have cold & windy conditions at the surface level mixed with air in the atmospheric level above that is flowing in a different direction. This causes rotation on a horizontal axis. If that is mixed with an updraft in the cloud formation it can tilt the rotation so that it looks like the formation is coming out of the bottom of the cloud. It is very similar to what we call a ‘Dust Devil’. In short, these are pretty spectacular to see but are usually benign.”
These funnel clouds usually only make it about halfway to the ground. Which is what Environment Canada believes has been happening today.
Stewart MacKay from Environment Canada said funnel clouds can be hard to detect on radar so they rely heavily on reports from people in the area which is why there were no advisories before the funnel clouds appeared.
“We can identify potential areas where funnel clouds might develop based on the surface and what is happening aloft. Generally that covers a fairly large area so we would be putting out funnel cloud advisories quite frequently. If that was the case, if we put them out or we thought we could detect them but there’s no guarantee that they’re going to happen. So typically, we’ll identify an area and unless it’s a really promising, they will usually sit back and wait and see what happens,” MacKay said.
MacKay says that there is a very minor concern, typically when funnel clouds are quite benign and generally a curiosity.
“They look kind of neat and don’t cause too many problems. There is the odd occasion where they may touch down on the ground generating a local strong wind event, so you could get some local damage, maybe a fence going down or some shingles knocked off a roof.”
Typically it would be very localized and not a lot of damage.
“Once we get the number of reports of funnel clouds and we can actually confirm their existence and we see some pictures, we’ll put out an advisory and obviously it’s more serious if someone reports that they are seeing several of them touchdown,” MacKay said.