The headline fire of this season in California was the Rim Fire which roared its way through Yosemite National Park. To date it has consumed nearly 256,000 acres and is still only 80% contained. There are a couple of reasons that may be attributed to the fires this year.
One is the fact that sometimes, fires are supposed to ‘cleanse’ the forest. This area of Yosemite has not had a big fire in quite a long time. So in a way it was ‘due’ for a wildfire due to lots of fuel waiting to be burned. In fact, there are some pine tree species that actually spread their seeds via wildfire! They explode when they reach a certain temperature, scattering their genes for the next generation.
But perhaps the main driver for this year is the exceptionally dry weather, which started last year. Over the course of the winter very few storms trekked across the state, bringing limited rain and well below average snowfall. That set the stage leading into the traditional dry season. This graphic shows the story. The period of January 2013-August 2013 was the driest such Jan-Aug ever recorded in the state. And it sticks out more than any other state in the country as being exceptionally dry.