Warm lakes and cold air are the most potent mix for lake-effect snow. Those perfect ingredients certainly came together on Wednesday leaving a significant mark on parts of Ontario's cottage country, with some waking up to about 50+ cm of snow on Thursday morning.
That's as one particularly dominant band parked itself right over the area on Wednesday night.
At one point Wednesday evening, Environment Canada issued a snow squall warning for the Bracebridge, Huntsville and Parry Sound area, warning of an intense and strong squall that had the potential to produce up to 75 cm locally. Unofficial reports indicate that as much as 50 cm had fallen in some areas, but with an additional 5-10 possible before the squalls gradually weaken through Thursday.
Bracebridge got a bit of snow a foot a snow #ONStormMuskoka411 News on Twitter
Little bit of snow in bracebridge last nightMadeline Stieler on Twitter
50 CM IN 24 HOURS, BUT HOW?
"Snow squalls are a very common weather phenomena in the late fall," says Weather Network meteorologist Jaclyn Whittal. "This is because we have very warm lake waters still from our summer season (it takes water a long to time to cool down) and we have extremely cold temperatures moving over the lakes."
If there's a 13 degree difference between the lake temperature and the air about 1.5 km up in the atmosphere, it's enough to get the lake-effect snow machine up and running.
"On Wednesday we had this magical equation with Georgian Bay sitting around around 6°C and the air above into the -20s," Whittal says. "Then the strong westerly winds brought several lake-effect bands right into cottage country."
WATCH: INTENSE SQUALLS PARKS OVER PARRY SOUND AREA
While there were several bands that moved through during the day, it was that one dominant band that took over and dropped the heaviest accumulations for some near Parry Sound.
"This can happen when you have good alignmemt from the surface well up into the atmosphere, allowing streamers to lock into place," Whittal explains, adding that this was much more snow than what was forecast for the region. "It is always difficult to nail down an exact snowfall forecast with lake-effect snow because one band, like the one we saw on Wednesday, can lock into place and drop huge amounts of snow."
That's while just ten minutes south or north could be in clear conditions with no precipitation at all.