Environment Canada has issued a snow squall watch for Barrie, Collingwood and Hillsdale, warning of potential travel hazards and lots of snow starting late Friday and continuing through the weekend.Flurries are forecast to begin Friday evening. By Sunday, Environment Canada predicts snowfall accumulation could exceed 40 centimetres in some areas, although the amounts could vary widely.The department is warning of “very poor visibility in bursts of heavy snow and local blowing snow” over the week