Temperatures are predicted to drop down to temperatures that are critical for bud survival in parts of the tree fruit producing areas of the province. I have heard reports that apples are at silver tip and even green tip and have seen scales separating in pears. Dr. John Cline from the University of Guelph has compiled a chart of Critical Spring Temperatures for Temperate Tree Fruit Flower Buds using data from Washington (WSU), Michigan (MSU) and North Carolina (NCS) Extension Bulletins converted to Celsius temperatures. Mark Longstroth from Michigan State University Extension compiled a MSU Critical Spring Temperatures on Tree Fruit Buds chart that includes pictures of the different bud development stages in Fahrenheit temperatures. You can also find recent bud hardiness data for tender fruit posted on the Tender Fruit Alert website for Niagara Region, Simcoe, Arkona and Blenheim.
Here is link for using wind machines to help protect against cold injury, keep in mind that wind machines are most effective when there is an inversion layer and more explanation is given in this factsheet: Wind Machines for Minimizing Cold Injury to Horticultural Crops Factsheet.
Irrigation for protection is not recommended for temperatures below -6.7 ˚C