Climate warming can bring more frequent and severe forest fires. This map shows the change in forest fire severity levels across Canada from 1980 to 1989, based on Global Generation Circulation Models. The Seasonal Severity Rating (SSR) is a measure of fire danger conditions over a complete fire season. The SSR is developed by averaging daily values over the season. The scale shown is relative, with values above 6 being extreme. A real value of zero is only possible in remote cold regions where no fire danger exists in the summer months.