Australia on Wednesday was grappling with an unprecedented heat wave that has sparked raging bushfires across some of the country’s most populated regions – pushing firefighters to their limits, residents to their wits’ end and leaving meteorologists tracking the soaring temperatures into uncharted territory.Four months of record-breaking temperatures stretching back to September of last year have combined over the past week with widespread drought conditions and high winds to create what the government had labeled "catastrophic” fire conditions along the heavily populated eastern and southeastern coasts of the country, where much of the population is centered. Data analyzed on Wednesday by the government-run Bureau of Meteorology indicated that Tuesday was the hottest day on record for the country – just one day after the previous record had fallen on Monday. Meteorologists have taken the extraordinary step of adding two new colors to its temperature charts to extend their range to 54 degrees Celsius (129 F) from the previous cap of 50 degrees Celsius (122 F) to account for the climbing temperatures. "If you look at yesterday, at Australia as a whole, it was the hottest day in our records going back to 1911.” said Dr. David Jones, manager of climate monitoring prediction at the Bureau of Meteorology. "From this national perspective, one might say this is the largest heat event in the country’s recorded history.” With the record-breaking heat, firefighters were struggling to contain the huge bushfires in Australia’s most populous state, New South Wales, which have swallowed around 324,000 acres of forest and farmland since they erupted on Tuesday. Fires on the island state of Tasmania off the country’s southern coast have destroyed 198,000 hectares since Friday. No deaths have been reported in connection with the fires, although about 100 people remain unaccounted for since a fire destroyed around 90 homes in the Tasmanian town of Dunalley, east of the state capital of Hobart, last week. And despite a brief respite from the searing heat in some coastal areas on Wednesday, the government has warned that the hot spell was only just getting started as the so-called "Dome of Heat” began moving up the eastern seaboard away from Sydney, where it was expected to deliver more blistering weather to Brisbane, Australia’s third largest city. Tuesday’s new high adds to a growing list of records the Bureau of Meteorology has recorded during this extended heat wave: the first time the country has recorded six consecutive days of temperatures above 39 Celsius; the year with the most record hot days in Australia since national records began in 1910, and nationwide average temperatures on each of the first six days of 2013 that were among the top 20 hottest days on record. Agencies