The wildfires that have so far claimed more than 170 lives in Australia highlight vulnerabilities in a country where the population is spilling into rural areas already under stress from sometimes extreme weather conditions.

Police suspect arsonists played a role in starting the blazes in Australia, one of the worst natural disasters in the country’s history.

Officials struggled to contain the flames, which obliterated at least two towns over the weekend and continued to burn Monday in grasslands and forests north of Melbourne, the capital of the southeastern state of Victoria.