Bush fires raging across some of the most populous parts of Australia — feeding off widespread drought conditions and high winds — pushed firefighters to their limits and residents to their wits’ end on Wednesday as meteorologists tracked the country’s hottest spring and summer on record into uncharted territory. Four months of record-breaking temperatures, stretching back to September, have produced what the government says are "catastrophic" fire conditions along the eastern and southeastern coasts of the country, where the majority of Australians live.