Sunny California Hasn't Been Very Sunny, Which Is Good for Stopping Drought

Sunny California Hasn't Been Very Sunny, Which Is Good for Stopping Drought

Good news! California’s drought is shrinking!

After over five years of parched conditions, January brought lots of rain and snow to California. There’s been so much precipitation that now about half the state is free from drought.

Yes, you could see this as a glass-half-empty situation as drought persists in the other half of the state and floods from the recent storms have caused calamity. But from a glass-half-full perspective, all the rain and snow is a big change from a year ago when nearly the entire state was in a drought, much of it severe.

There was no water to be seen in Folsom Lake, California in November 2015 because of the drought.

Credit: Public Domain Picture

A drought is a long period of unusually dry weather. But there is not an exact amount of dry weather that constitutes a drought because it is relative to the typical amount of rain and snow (precipitation) in an area. This typical amount of precipitation is defined as a part of a region’s climate and is calculated as a 30-year average.

The interesting thing about California is that the state is so large that it has several different regional climates. In general, Northern California is more moist with a Mediterranean climate according to the Koppen Climate Classification system. Southern California is drier with areas of semi-arid or desert climate. There’s also a small area of subarctic conditions in the Sierra Nevada mountain range.

Because climate varies through the state, so does the average precipitation. Some areas in Southern California receive five inches of precipitation or less per year on average. Other areas, like coastal Northern California, receive one hundred inches of precipitation in an average year.  What’s normal in these two areas is different. The amount of moisture during drought conditions in Northern California would look like extremely wet conditions in Southern California.

Average annual precipitation (inches) in different parts of California
Credit: adapted from the U.S. Geological Survey

There are different amounts of drought. Some of the land in California is currently in mild drought conditions, somewhat drier than normal. Other areas are experiencing moderate, severe, or extreme drought. Below, the map of drought conditions from the website indicates the areas of California and Nevada that are in drought. Notice that it is areas like Southern California that are usually dry. In a drought, these areas are even drier.

Map of drought in California, January 24, 2017.  
Credit: adapted from Richard Tinker, CPC/NOAA/NWS/NCEP 


The area impacted by drought in California is shrinking, but there are still areas of drought throughout the United States. In January, over 100 million people in the U.S. were living in drought conditions. Drought can be natural, but climate change is changing precipitation, increasing the chance of drought in many areas.  You can keep track of drought at the website provided by the National Oceanic and Atmospheric Administration (NOAA) and find out if there’s a drought where you live. 

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