Indicators

The Importance of Snowpack

by Mike Kolian

In the United States, changes in snowpack currently represent one of the best documented hydrological signs of climate change. Snowpack is a key indicator and plays a vitally important role both in the environment and to society.

Snowpack accounts for a majority of water supply in many parts of the West as it stores vast amounts of water that is slowly released as temperatures rise in the spring and summer. Snowpack keeps the ground and soil moist by covering it longer into spring and summer which influences the onset of the fire season as well as the prevalence and severity of wildfires. In addition, hydro-electric power generation in the West is heavily reliant on water supplied by melting snowpack.

A very serious story is unfolding out West. This year, snowpack in the western U.S. is at record lows in the Sierra Nevada and Cascades of California, Oregon, and Washington, confirmed by the recent April 1st snowpack measurements. In fact, some snowpack sites in California and Washington were observed to be snow-free this spring for the first time since observations began.

Snowpack is measured in snow-water equivalent, which reflects the amount of water contained in the snowpack at a location (if the entire snowpack were to melt). This indicator is based on data from over 700 measurements sites across 11 western states and shows long-term rates of change for the month of April, which could reflect changes in winter snowfall as well as the timing of spring snowmelt.

map chart titled "Trends in April Snowpack in the Western United States 1955-2015." Charts shows mostly percentage reductions of snowpack over all mountains areas, ranging from 0 to -80 percent. Very few areas show small increases.

Over the last 60 years, there have been widespread temperature-related reductions in snowpack in the West, with the largest reductions occurring in lower elevation mountains in the Northwest and California. From 1955 to 2015, April snowpack declined at over 90 percent of the sites measured (see map). The average change across all sites amounts to about a 14 percent decline. Observations also indicate a decrease in total snowfall and a transition to more rain and less snow in both the West and Northeast in the last 50 years.

photo of a resevoir with water levels dropped way below usual level

Long-term trends in snowpack provide important evidence that climate-related shifts are underway, and highlight the seriousness of water-resource and drought issues that Western states such as California currently face.

Less snowpack means less water and less water means more serious impacts.

Explore more:

See this and other Snow and Ice indicators

Open the map in Google Earth (KMZ) (100K, Download Google Earth): http://www.epa.gov/climatechange/images/indicator_downloads/snowpack_april1.kmz

About the author: Mike Kolian is an environmental scientist with EPA’s Office of Atmospheric Programs, Climate Change Division. His deep roots managing long-term environmental monitoring programs form the basis of his appreciation for the important role they and their data play in scientifically based decision making.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Changing Times: EPA’s Report on National Trends

By Gaelle Gourmelon

Some things in my childhood memories look different when I revisit them as an adult. That tall slide in the playground? It’s really only four feet high. The endless summer bike rides to the beach? They now take ten minutes. Sometimes, however, things seem different because they’ve actually changed. I recently went to a favorite childhood beach and saw that the dock was now stranded in the water, no longer reachable from the beach. Undeniable evidence of the changing coast.

But what evidence do we have to observe real changes over time when it comes to our national environment? What data can we use to determine if our environment has meaningfully changed?

To help answer these questions, EPA released the draft Report on the Environment 2014 (ROE 2014) for public comment in March, and it will undergo external peer review on July 30-31, 2014.

The ROE 2014 is not an intimidating, technical tome; it is an interactive website, full of national-level environmental and health indicators and is designed to make it easier to find information on national environmental trends. It’s not a giant, unwieldy database. Rather, it’s a summary of important indicators that paints a picture of how our environment is changing.

Why use indicators?

Just like having a high temperature indicates you are sick, environmental indicators help us understand the health of the environment. ROE indicators are simple measures that track the state of the environment and human health over time.

For example, if we want to understand the nation’s air quality, we can measure indicators such as lead emissions, acid deposition, and particulate matter concentrations to give us clues about overall changes. These indicators can help us make informed decisions about conditions that may otherwise be difficult to measure.

Report on the Environment

An exhibit for the acid deposition indicator gives us a clue about the changes in the quality of outdoor air in the US.

 

What’s included in the Report on the Environment?

Data for the ROE indicators come from many sources, including federal and state agencies as well as non-governmental organizations. EPA brought together scientists and other experts to determine what data are accurate, representative, and reliable enough to be included. With feedback from the public and our partners, we selected 86 indicators that help to answer questions about air, water, land, human health and exposure, and ecological condition. The ROE 2014 also includes new indicators on aspects of sustainability.

Why do we need the Report on the Environment?

EPA designed the ROE to help answer mission-relevant questions and help us track how we’re doing in meeting environmental goals. But because the ROE 2014 is an easy-to-use, interactive website, scientists, decision-makers, educators, and anyone who is curious about the environment and health can view the most up-to-date national (and sometimes regional) data, too. The ROE shows trends and sets up baselines where trend data do not yet exist. It also highlights gaps where we don’t have reliable indicators.

How can I participate in the external peer review meeting?

EPA is committed to proactively engaging stakeholders, increasing transparency, and using the best available science. By releasing the draft ROE 2014 for public comment and peer review, we benefit from stakeholder and scientific engagement to support the best conclusions possible. The draft ROE 2014 website will be reviewed by EPA’s Science Advisory Board in a public meeting on July 30-31, 2014. For additional meeting details, visit the July 11, 2014 Federal Register Notice and the SAB meeting website.

How can I stay connected with the ROE?

Everyone can use the ROE to inform their discussions of environmental conditions and related policies in the U.S. The information it provides helps you understand your environment, and encourages you to ask more questions about your environment and health. Now, it’s time to investigate. Things might have changed more than you think.

Sign up to be notified about the upcoming release of the final Report on the Environment 2014; you can also receive periodic updates and highlights.

About the author: Gaelle Gourmelon was an Association of Schools and Programs of Public Health Fellow working on EPA’s Report on the Environment project from September 2012 through May 2014. Her background in biology and environmental health has fueled her passion for reconnecting people with their natural and built environment.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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How’s the Bay Doin’?

By Tom Damm

When the late New York City Mayor Ed Koch wanted to get a sense for, “How’m I doin’?” he’d ask people on the street.

Bay Barometer Cover ImageThe Chesapeake Bay Program takes a more scientific approach when it considers the state of the Bay and its watershed.

It crunches all sorts of statistics and produces an annual update on health and restoration efforts called Bay Barometer.  The latest one is now available.

So how’s the ecosystem doin’?

The science-based snapshot shows that while the Bay is impaired, signs of resilience abound.

A number of indicators of watershed health, like water clarity and dissolved oxygen levels, point to a stressed ecosystem.  But other factors, such as a smaller than normal summertime dead zone and an increase in juvenile crabs entering the fishery, provide a brighter picture.

Recent restoration work and pollution cuts also offer signs of progress for the nation’s largest estuary.

Learn more about Bay Barometer or read the full report.

About the Author: Tom Damm has been with EPA since 2002 and now serves as communications coordinator for the region’s Water Protection Division.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.