An illustration of three mountain peaks slowly turning blue to represent accumulating snow

How the last 20 years of Sierra snowpack stack up, in one?graphic

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The Sierra snowpack has reached its seasonal peak.

The snowpack plays an important role in providing water to millions of Californians. Throughout the winter months, snow accumulates on the high peaks of the Sierra Nevada and slowly melts in the spring and early summer. The runoff fills dozens of major reservoirs downstream.

Last year’s epic snowpack helped relieve a yearslong drought, reaching an eye-popping 252% of normal on April 8. By that date, the mountains held an average equivalent of 64.2 inches of water.

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The current snowpack now holds a healthy 28.6 inches of water on average after a series of winter storms alleviated concerns that California was facing a “snow drought.”

The California Department of Water Resources tracks the snow water equivalent in the Sierra using a network of 130 electronic sensors. The system went online in 1990s and began producing daily data in the early 2000s. Before that, officials relied on monthly snow surveys to measure the snowpack.

This graphic plots a 20-year history of the Sierra snowpack, showing wet years interspersed with severe droughts.

20 years of Sierra snowpacks

Drier/wetter conditions

Drier Wetter
This visualization stacks up 20 years of snowpack data. It shows how many long spells of drought are often broken by one or two very wet or average years with large snowpacks.

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

2005

Snowpack peaked at 45.5 inches on April 18, 2006

2006

2007

2008

2009

2010

2011

2012

2013

2014

The smallest modern snowpack came in at 5.6 inches on Feb. 9, 2015

2015

2016

47.8 inches

April 17, 2017

2017

2018

2019

2020

2021

2022

64.2 inches

April 8, 2023

2023

28.8 inches

March 31, 2024

2024

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

This visualization stacks up 20 years of snowpack data. It shows how many long spells of drought are often broken by one or two very wet or average years with large snowpacks.

Oct.

Dec.

Feb.

April

June

Aug.

2005

Snowpack peaked at 45.5 inches on April 18, 2006

2006

2007

2008

2009

2010

2011

2012

2013

2014

The smallest modern snowpack

came in at 5.6 inches on Feb. 9, 2015

2015

2016

47.8 inches

April 17, 2017

2017

2018

2019

2020

2021

2022

64.2 inches

April 8, 2023

2023

28.8 inches

March 31, 2024

2024

Oct.

Dec.

Feb.

April

June

Aug.

This visualization stacks up 20 years of snowpack data. It shows how many long spells of drought are often broken by one or two very wet or average years with large snowpacks.

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

2005

Snowpack peaked at 45.5 inches on April 18, 2006

2006

2007

2008

2009

2010

2011

2012

2013

2014

The smallest modern snowpack came in at 5.6 inches on Feb. 9, 2015

2015

2016

47.8 inches

April 17, 2017

2017

2018

2019

2020

2021

2022

64.2 inches

April 8, 2023

2023

28.8 inches

March 31, 2024

2024

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

This visualization stacks up 20 years of snowpack data. It shows how many long spells of drought are often broken by one or two very wet or average years with large snowpacks.

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

2005

Snowpack peaked at 45.5 inches on April 18, 2006

2006

2007

2008

2009

2010

2011

2012

2013

2014

The smallest modern snowpack came in at 5.6 inches on Feb. 9, 2015

2015

2016

47.8 inches

April 17, 2017

2017

2018

2019

2020

2021

2022

64.2 inches

April 8, 2023

2023

28.8 inches

March 31, 2024

2024

Oct.

Nov.

Dec.

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

When stacked up, the last two decades reveal California’s quintessential pattern of bust and boom. When California faces long dry spells, it takes large amounts of snow and rain to reverse the trend.

This cycle is projected to become more extreme as the planet warms. With human-caused climate change, higher temperatures are intensifying droughts, and the state’s average snowpack is projected to shrink significantly as temperatures continue to climb.

Tracking the rise and fall of California’s snowpack over the past two decades provides a long-term view of the state’s highly variable climate and the patterns that dictate our water fortunes.

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