Drought spread and intensified this week in seven western and central states, including California, Oregon, Nevada, Arizona, New Mexico, Texas and Oklahoma, according to the U.S. Drought Monitor, a federal site that tracks drought.
This week marks the first time in the 15-year history of the Monitor that 100% of California was in moderate to exceptional drought.
The cost of the drought in California is estimated at least $7.48 billion in direct and indirect costs, according to Mike Wade, executive director of the California Farm Water Coalition. This includes crop losses and about 20,000 job losses tied to 800,000 acres of idled farmland.
The amount of acres idled equals the size of Los Angeles, San Diego, San Jose, Fresno and Bakersfield combined — some 1,250 square miles.
Crops such as iceberg lettuce, broccoli, bell peppers, cantaloupes and tomatoes are being hardest hit, the farm coalition reports.
"If you combine the current drought with the nearly $450 million in damage to the state's citrus crop from a freeze last December, the state's agriculture has really had a rough couple of months," says Steve Bowen, a meteorologist with Aon Benfield, a global reinsurance firm based in London.
"If the intensity of the drought remains prolonged, the economic cost will surely continue to grow," he says.
The worst of the drought in California is centered in the west-central part of the state.
The city of Montague, in northern California, risks running out of drinking water by the end of summer and has requested that all outside watering be reduced until further notice, according to the Monitor. This is the first time in over 80 years that this has occurred.
More than 60% of the West is in some form of drought. Only Montana and Wyoming are completely drought-free.
The main cause of the recent intensifying of the drought is a persistent weather pattern that kept storms from the region for much of the winter, according to meteorologist Richard Heim of the National Climatic Data Center in Asheville, N.C.
The pattern consisted of a cold trough of low pressure over eastern North America (responsible for the cold winter) and a warm, dry ridge of high pressure over the eastern North Pacific Ocean and western North America, Heim said. High-pressure ridges prevent clouds from forming and precipitation from falling.
A study earlier this month in Geophysical Research Letters by scientists at Utah State University suggested that the type of "stuck" climate pattern that caused the drought could be linked to climate change. But much more research will need to be conducted on the subject to reach any definitive conclusions.