Thursday’s release of the current drought monitor showed significant upgrades to drought severity across California, including the Sierra, Central Coast and into Southern California.
An extremely dry start to fall punctuated by dry offshore winds led to the changes, according to Dan McEvoy, applied climatologist with the Desert Research Institute.
This year has been perhaps the most extreme example yet of a shortened rain season and expansion of the fire season made worse by record-setting evaporative drought demand index (EDDI) that has been literally off the charts compared to previous years.
McEvoy explained it’s this “atmospheric thirst” that leads to more rapid growth of wildfires — as we’ve seen throughout this record-setting fire season with more than 4 million acres burned vs. the roughly 600,000 acres burned/year average.
As rain returns to the forecast, McEvoy explained that if rainfall totals are above average for an extended period of time, we should begin to see the current drought footprint slowly decrease in regional coverage and intensity.
This is usually the case for the month of December, typically one of the wettest for the Bay Area. But, so far, not so much in 2020, a year of all-time extremes in California for wildfires, smoke pollution and heat.