California is experiencing unusual winter fires given the driest conditions the region has experienced in its recorded history - normally wet areas like Big Sur, for example, are ablaze. These conditions aren't unique to California, as Hawaii has experienced record-breaking drought conditions over the last few years, spurring an increase in the frequency, size, and severity of fires across all of the islands.
From the Source:
“California and parts of western Oregon witnessed their driest year on record in 2013, according to statistics from the National Weather Service (NWS)...
A critical season looms for the nation's most populous state, struggling through its third straight dry winter.
The culprit for this dearth of rain and mountain snow is a persistent ridge of high pressure aloft over the eastern north Pacific Ocean, which has diverted the jet stream, and hence, the storm track, well to the north into Canada.
The few storm systems that have penetrated the West Coast recently have tended to drop south out of western Canada as relatively moisture-starved systems, rather than sweeping in ashore from west to east, tapping deeper moisture.
Are there any signs of the pattern turning wetter? In a word, 'no'."
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Above: "Drought status of the western U.S. as of Dec. 24, 2013. Areas of worse drought are indicated by the progressively more tan/brown contours. (NOAA/USDA/NDMC)."