An emergency warning for the outskirts of Perth, the country’s fourth-largest city, was issued after a blaze that has now burned through about 100 hectares began Tuesday. Authorities are concerned about the fire reaching residential areas, as fierce winds strain containment lines. Emergency services have told residents they are “in danger and need to act immediately to survive. There is a threat to lives and homes”. Perth is forecast to hit 34 degrees Celsius (93.2 degrees Fahrenheit) on Wednesday before ramping up to near 40C (104F) until Saturday. WIND INTENSITY THE PROBLEM“The emergency war…