The most recent edition of the federal United States Drought Monitor map indicates worsening drought conditions throughout California, with “extreme drought” affecting virtually the entire San Francisco Bay Area zone.
The chart uses a color-coded scale to categorize the severity of the drought, from “abnormally dry” (yellow) to “exceptional drought” (red) (maroon). The most extreme conditions are forming along the state’s southern boundary with Nevada and Arizona, according to the April 29 map. The “Extreme drought” (red) affects most of southern and northern California, while the “severe drought” (orange) affects the majority of the state.
“The presence of drought on the map is no surprise — especially in Northern California,” wrote Richard Heim, a National Oceanic and Atmospheric Administration meteorologist who was one of the map’s writers this week. California has seen a string of dry winters, with the most recent becoming the third driest on record.
The last drought in California lasted from 2012 to 2016, and at its peak in 2014, the whole state — 100 percent — was under moderate to extraordinary drought from May 13, 2014, to July 29, 2014, and 81.92 percent was under exceptional to serious drought from August 5, 2014, to October 28, 2014, according to Heim.
Currently, moderate to extraordinary drought affects 87.95 percent of the nation, with serious to serious drought accounting for 52.86 percent.
“So, while it’s bad now, in the recent past it has been worse,” he added.
Every Thursday, the federal government publishes a new Drought Monitor chart showing drought conditions throughout the world, which is widely shared by news media and Twitter users, causing the map to go viral.
The chart has become a poster child for a looming drought as the sum of red showing severe drought rises every week as the condition in California worsens.
While the chart is an interesting aspect of the tale, Jeanine Jones, California’s drought manager for the state’s Department of Water Resources, stressed that the graphic that fits on one page does not include a full view.
The Drought Monitor is a collaboration between NOAA, the US Department of Agriculture, and the University of Nebraska-National Lincoln’s Drought Mitigation Center. The weekly chart is not a prediction, but rather a reflection of the previous week’s precipitation.
The chart indices a broad range of metrics, including groundwater storage, river flows, soil moisture, satellite-based measurements of plant quality, and more, in addition to precipitation totals.
The chart is a mechanism for measuring drought that is mostly used in agriculture, and it is used by the United States Department of Agriculture to make recommendations on agricultural financial assistance.
“You’ve probably seen some of the stories talking about the USDA designating California an agricultural disaster area; what they’re referring to is based on the drought monitor,” Mrs. Jones, California’s drought specialist with the state’s Department of Water Resources said, referring to the USDA’s April 5 announcement of minimal loans to help drought-stricken farmers and ranchers.