A major winter storm is expected late this week into the holiday weekend.
A Special Weather Statement has been issued for Niagara and much of Ontario with rain or snow starting Thursday night, and then temperatures dropping Friday - leading to a possible 'flash freeze'.
The rapidly falling temperatures will be accompanied by strong to potentially damaging winds along with snow that may be heavy at times.
Environment Canada says it's hard to predict exactly how much snow will fall right now.
"Consider altering plans through the holiday weekend as travel conditions may become dangerous. Extensive utility outages are possible. Temperatures Friday night into the weekend will likely be the coldest of the season to date."