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Snowpack: Decadal Averages Map


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12km x 12km pixel grid
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Use these buttons to control the map.
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Map Animation
Use these buttons to watch the map overlay reflect the change in snowpack over time.
  • Click the Play button to begin the animation.
  • Click the Toggle button to alternate between the beginning and end of the available years. The beginning year displays temperature averages projected into the past, and the end year displays temperature averages projected into the future.
  • Use the Slider to control the speed of the animation.
The timeline displays which decade you are currently viewing on the map. You can manually drag the handle to change the year in view.
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The Legend displays the range of values visible on the map overlay for the variable being displayed (temperature degrees, inches of rainfall, area burned, etc).
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Click anywhere on the map to see a chart for this area.

Using the Area Selection Type Menu to the left, edit types of selection areas:

  • grid cells, where each cell is an area of 12km x 12km
  • predefined county boundaries

Then click anywhere on the map to automatically change the area described in the chart.

Select various chart options in the dropdown menus to the right, which can include Month, Model, and Temperature ranges (High, Low, or Average).

Note: The first set of chart options control the variables being viewed on the map.

Add a Chart for comparison

Click "Add Chart" to create an additional chart to compare with. After creating the new chart, click on a new area of the map to view a chart for the same options in another location. Or change an option in the dropdown menu to view the chart for the same location, with different settings.

To edit the first chart again, either directly edit the dropdown menus, or click on the Location Name and then click on a new location on the map.

Click "Predefined boundaries" in the Area Selection Type Menu to the left before clicking on an area of the map, if you'd like to compare counties to one another.

Lock Location

Fix the locations of the graphs to one area by clicking this toggle.



If heat-trapping emissions continue unabated, more precipitation will fall as rain instead of snow, and the snow that does fall will melt earlier, reducing the Sierra Nevada spring snowpack by as much as 70 to 90 percent.

How much snowpack will be lost depends in part on future precipitation patterns, the projections for which remain uncertain. However, even under wetter climate projections, the loss of snowpack would pose challenges to water managers, hamper hydropower generation, and nearly eliminate skiing and other snow-related recreational activities.

If global warming emissions are significantly curbed and temperature increases are kept in the lower warming range, snowpack losses are expected to be only half as large as those expected if temperatures were to rise to the higher warming range.

Use the slider bar to the left to visualize the projected change insnow water equivelence, as seen in the low and higher emissions scenarios. Adjust the options below to view different models, and months.

Take a Tour

Emissions Scenario:

Create a chart by clicking a location on the map and altering one of the dropdown option boxes.


Create a chart by clicking a location on the map and altering one of the dropdown option boxes.


This information is being made available for informational purposes only. Users of this information agree by their use to hold blameless the State of California, and its respective officers, employees, agents, contractors, and subcontractors for any liability associated with its use in any form. This work shall not be used to assess actual coastal hazards, insurance requirements, or property values and specifically shall not be used in lieu of Flood Insurance Studies and Flood Insurance Rate Maps issued by the Federal Emergency Management Agency (FEMA).


The data presented in this tool are projections of future climate. They are not weather predictions and should not be treated as such. Climate projections tell us how weather conditions are likely to change on average, but they cannot predict the weather at a particular day and time. Learn more about what climate models can and cannot tell us.

Although climate models are powerful and effective tools for simulating the climate system, there is some uncertainty inherent in any projection of the future, and climate model projections are no exception. For example, climate model projections illustrate how the climate system is expected to behave under specific scenarios of greenhouse gas emissions. Since our emissions of greenhouse gases depend on a variety of different social, political, and economic factors, we cannot be certain how they will change. Therefore, projected climate data may not prove to be accurate if the actual emissions pathway we follow differs from the scenarios used to make the projections.

Another source of uncertainty in climate projections is the fact that different climate models—the tools used to simulate the climate system and produce future climate data—may produce different outcomes. There are more than 30 global climate models developed by climate modeling centers around the world, and they have different ways of representing aspects of the climate system. In addition, some aspects of the climate system are less well understood than others. Climate scientists are constantly working to improve our theories of the climate system and its representation in climate models. In the meantime, one way to account for model differences is to look at projections from many different models to get a range of possible outcomes. You can then take the average of the values across the different models, and this average value is a more likely outcome than the value from any single model. The default visualizations in this Cal-Adapt are based on the average values from a variety of models. Find out more about climate change data.

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Snowpack: Decadal Averages Map

Climate data provided by:

Scripps Institution of Oceanography

California Nevada Applications Program (CNAP)

Data Set Contributed: Projected Snow Water Equivalent

Projected monthly Snow Water Equivalent (amount of water contained within the snowpack). These data layers were downscaled using a bias correction and spatial downscaling (bcsd) approach and include data for four different models (PCM1, CCSM3, GFDL, CNRM) for two different scenarios (A2, B1).

Related Stories

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Securing an Adequate Water Supply

2011 April 12

Continued global warming will increase pressure on California’s water resources, which are already over-stretched by the demands of a growing economy and population. Decreasing snowmelt and spring stream flows coupled with increasing demand for water resulting from both a growing population and hotter climate could lead to increasing water shortages. By the end of the century, if temperatures rise to the medium warming range and precipitation decreases, late spring stream flow could decline by up to 30 percent. Agricultural areas could be hard hit, with California farmers losing as much as 25 percent of the water supply they need.

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Informing improved water management in the face of current and future climate variability

2013 December 05

A decade of collaboration between scientists and California water managers has led to the development of a probabilistic-based decision-support software, called INFORM (Integrated Forecast and Reservoir Management).

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Mountain Issue: Climate Change on the Slopes

2015 March 02

A visible sign of the effects of climate change can be seen on the snow-less mountains of California, where many ski areas have been unable to operate this season. With the loss of snowpack in California, local winter sports resorts have been making the news, from Mt. Waterman in Southern California to Lake Tahoe in Northern California.


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