Will El Nino End the Drought?

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Drought Conditions / May 1, 2016

Photo: Frank Gehrke of the California Department of Water Resources measuring the Sierra snowpack.


Upper Colorado River Basin
% of Median May 1st


Northern Sierra
% of Average May 1st


Lake Cuyamaca Basin
% of Average Annual Total
Rain & Snowfall


Lake Mead
% Full on May 1, 2016


Lake Oroville
% Full on May 1, 2016


Lake Cuyamaca
% Full on May 1, 2016

How Much Precipitation California Needs

 Every region in California is missing at least a year’s worth of precipitation. In fact, the south coast of California Is missing almost two year’s worth of rain (1.82 years to be exact). This deficit isn’t so much a hole as a giant chasm.

Tom Di Liberto

National Oceanic and Atmospheric Administration (NOAA)

The map on the left shows how much precipitation we need in 2016 to pull our five year precipitation total — from 2011 to 2016 — out of the bottom 20 percent of historical five year precipitation totals in California. The map on the right shows how much precipitation we need to move into the top 50 percent of historical five year precipitation totals.

Source: NOAA

Photo: Lake Oroville, the source of water for California’s State Water Project, in October 2015.

What to Expect from El Nino

By January, February and March we’ll see above average precipitation — potentially well above average.

Daniel Swain

Climate Scientist, Stanford University

The NOAA’s Climate Prediction Center estimates the chance of El Nino bringing a wetter-than-average winter in 2016 at:

> 60%
in Southern California

> 40%
at Lake Oroville, the water source for the State Water Project

> 40%
in the Upper Colorado River Basin

What Causes Drought

Many factors influence precipitation and temperature, and both influence the severity of drought. However, if you want to know why California has not received its usual chain of winter storms in the last four years, take a look at the satellite image below.  It shows what climate scientists at Stanford University named The Ridiculously Resilient Ridge, a high pressure ridge off the west coast of North America. The ridge formed and remained in place for most of the winter in 2012, 2013, 2014 and 2015, blocking winter storms bound for California and diverting them into the Arctic.

Read About the Ridiculously Resilient Ridge

The Effects of Four Years of Drought


Wells and creeks ran dry in 2013 leaving small communities like East Porterville without water.

Drought vs. People


Northern California rivers are too warm for native Chinook Salmon and their eggs to survive.

Drought vs. Salmon


In 2015, drought-related losses in California’s agricultural sector reached $2.7 billion.

Drought vs. Agriculture


Low reservoirs have reduced statewide hydropower production to 1/3 of normal.

Drought vs. Hydropower


Aerial surveys have identified millions of drought-stressed trees vulnerable to bark beetles and fire.

Drought vs. Forests


Wildfires are sweeping across the West, fueled by hot, dry conditions.

Drought & Wildfire

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