Amount

This map shows how much April snowpack has changed from 1982 to 2020.

Each circle represents a different site in the western United States.

• Negative percentages, shown in red, indicate decreased snowpack.
• Positive percentages, shown in blue, indicate increased snowpack.

Timing

This map shows how the date when snowpack reaches its maximum amount has changed from 1982 to 2020.

Each circle represents a different site in the western United States.

• Negative values, shown in red, indicate a shift to earlier days.
• Positive values, shown in blue, indicate a shift to later days.

Notes

By Jack J. Lee

Data from the U.S. Environmental Protection Agency

Files available on Github.