Heat changes the water cycle and creates a thirstier atmosphere that accelerates evaporation. This year, even before the summer, it is already nearly gone.
The melt has also produced less runoff than expected, meaning less trickled into streams, rivers and reservoirs. Well, that's it. California's winter snowpack is basically gone. Two months early. The impact is a lot more than it was in the past. Dry conditions are also expected to fuel another potentially devastating wildfire season. In , roughly 4. The browning hillsides and dying trees are not only increasing the risk of ignitions, they also cause fire behavior to be more extreme when blazes erupt, according to Scott Stephens, a fire ecologist at the University of California, Berkeley.
Already farmers are culling crops and fallowing fields in anticipation of water shortages. Cities and other urban regions are also set to receive less water, and residents are being asked to conserve where they can. The researchers analyzed year data sets that recorded precipitation, ocean evaporation, surface wind speed and atmospheric pressure on and near the west coast of the United States. These are all factors that influence the water cycle in California.
One of the difficulties of studying the water cycle, Wei said, is that the water sources for precipitation cannot be directly observed, so the team also used a mathematical moisture-tracking method and high-resolution model simulations. Federal government websites often end in. The site is secure. The U. This map shows drought conditions across California using a five-category system, from Abnormally Dry D0 conditions to Exceptional Drought D4.
Learn more. The following state-specific drought impacts were compiled by the National Drought Mitigation Center. While these impacts are not exhaustive, they can help provide a clearer picture of drought in California.
View up-to-date drought conditions down to the city and county level, including temperature, and precipitation conditions, key drought indicators, outlooks, historical conditions, and water supply, agriculture, and public health maps. Drought Monitor started in Since , the longest duration of drought D1—D4 in California lasted weeks beginning on December 27, , and ending on March 5th, The most intense period of drought occurred the week of July 29, , where D4 affected The USDM relies on drought experts to synthesize the best available data and work with local observers to interpret the information.
The USDM also incorporates ground truthing and information about how drought is affecting people, via a network of more than observers across the country, including state climatologists, National Weather Service staff, Extension agents, and hydrologists.
The Standardized Precipitation Index SPI is an index to characterize meteorological drought on a range of timescales, ranging from 1 to 72 months.
The SPI is the number of standard deviations that observed cumulative precipitation deviates from the climatological average. Tree-rings are used to extend the instrumental record of drought to over years.
This dataset blends tree-ring reconstructions and instrumental data to estimate the average summer PMDI values, which extend over years in some parts of the U.
California State Climatologist.
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