There was inevitability about California state governor Jerry Brown’s declaration of a drought emergency on Friday.
90% of the state is in the grip of a severe drought, said to be the worst in more than a century. This comes after the US’s most populous state experienced its driest year since record began in 1849.
San Francisco recorded annual precipitation of 86mm in 2013, just 16% of the long term average of 524mm. This pattern was repeated in most of the state’s major cities. Only San Diego recorded more than half its long term average (54%).
Brown’s declaration came just a day after a major wildfire began in the southern portion of the state. Although the Colby Fire, near Azura, is now more than 80% contained, officials fear it could be a sign of what they will be facing on a regular basis in the coming months.
Strong winds, tinder-dry vegetation and low humidity have provided ideal conditions for wildfires.
Although the lack of rainfall is a concern, more than 80% of the state’s drinking water originates in the snowfields of the Sierra Nevada Mountains to the east.
Yet, as the NASA images (above) which were captured exactly one year apart show, snow cover is 80% down on that of 2012.
The state’s reservoirs are already responding to the reduced inflow. Lake Shasta reservoir, California’s largest, is at half its normal level and settlements from the nineteenth century Gold Rush are being exposed by falling water levels at the Fulsom Lake reservoir in the north of the state.
Governor Brown has called for a voluntary 20% reduction in water consumption, but he is well aware that demand for water is increasing dramatically as the population of California has nearly doubled in the last 40 years.
Farmers and growers are particularly concerned about the drought. Agriculture generates almost $45 billion in revenue for the state and uses some 80% of available drinking supplies.
The current set-up of the jet stream, a band of high-level winds, is keeping the west of the US under an area of high pressure, displacing much-needed rainfall towards the Midwest. Currently there is nothing to suppose that any significant change is on its way. So California may be forced to use more of its precious but dwindling water resources to fight more wildfires through the spring and summer months.