JPL climate scientist Bill Patzert wrote a nice op ed in the San Gabriel Valley Tribune about weather, climate and fire that got me thinking about my old home turf of Southern California yesterday:
What set us up for these fires? Rain has been scarce. A large-scale drought has strangled the American Southwest for almost a decade, four years of below-normal rainfall have parched the Southland, and six months with almost no rain at all have turned our foothills dangerously dry.
I’m more focused on my part of the southwest now, so I haven’t followed the numbers closely, but was amazed when I went back and looked at the data:
That’s the annual precipitation for 12-month periods ending in August (not a normal window of time, but it allowed me to capture the last 12 months). The green line is the long term average. In the last decade, there has been one unusually wet year, two that were sort of average, and the other seven have been extremely dry.
But here’s the kicker in terms of thinking about drought conditions. Remember my new meme – it’s not just precip, it’s evaporation? Look at the temperatures:
Again, green is average.