Sierra Nevada snowpack lowest in five centuries

Related Articles

Snowpack in California’s Sierra Nevada in 2015 was at the lowest level in the past 500 years, according to a new report led by University of Arizona researchers.

The team’s research is the first to show how the 2015 snowpack compares with snowpack levels for the previous five centuries.

“Our study really points to the extreme character of the 2014-15 winter. This is not just unprecedented over 80 years — it’s unprecedented over 500 years,” said Valerie Trouet, an associate professor of dendrochronology at the UA Laboratory of Tree-Ring Research.

 

“We should be prepared for this type of snow drought to occur much more frequently because of rising temperatures,” Trouet said. “Anthropogenic warming is making the drought more severe.”

California’s current record-setting drought began in 2012, the researchers note in their report.

On April 1 of this year, California Gov. Jerry Brown declared the first-ever mandatory water restrictions throughout the state while standing on dry ground at 6,800-foot elevation in the Sierra Nevada. The historical average snowpack on that site is more than five feet, according to the California Department of Water Resources.

These two natural-color satellite images of the snow cover in the Sierra Nevada in California and Nevada show the last year with average winter snowfall, 2010, compared with 2015 -- a year that had the lowest snowpack in 500 years. The images were taken by the Moderate Resolution Imaging Spectroradiometer on NASA's Aqua satellite. CREDIT : NASA/MODIS
These two natural-color satellite images of the snow cover in the Sierra Nevada in California and Nevada show the last year with average winter snowfall, 2010, compared with 2015 — a year that had the lowest snowpack in 500 years. The images were taken by the Moderate Resolution Imaging Spectroradiometer on NASA’s Aqua satellite. CREDIT : NASA/MODIS

The lack of snow in 2015 stems from extremely low winter precipitation combined with record high temperatures in California in January, February and March, Trouet said. About 80 percent of California’s precipitation occurs in the winter months, she said. Snowpack level is generally measured on April 1 each year, a time when the snowpack is at its peak.

“Snow is a natural storage system,” she said. “In a summer-dry climate such as California, it’s important that you can store water and access it in the summer when there’s no precipitation.”

In past years the snows of the Sierra Nevada slowly melted during the warmer months of the year, and the meltwater replenished streams, lakes, groundwater and reservoirs. In a winter with less snow or with winter precipitation coming as rain rather than snow, there is less water to use during California’s dry summers.

First author Soumaya Belmecheri said of the extremely low snowpack in 2015, “This has implications not only for urban water use, but also for wildfires.”

Belmecheri is a postdoctoral research associate at the UA Laboratory of Tree-Ring Research.

To figure out snowpack levels for the past 500 years, Trouet and her colleagues used previously published tree-ring data that reflects annual winter precipitation in central California from 1405 to 2005 and annual snowpack measurements since the 1930s. The team also used a previously published reconstruction of winter temperatures in southern and central California that spanned the years 1500 to 1980.

Trouet, Belmecheri and their colleagues’ report, “Multi-century evaluation of Sierra Nevada snowpack,” is scheduled for online publication in Nature Climate Change on Sept. 14, 2015.

Co-authors are Flurin Babst of the UA Laboratory of Tree-Ring Research, Eugene R. Wahl of the NOAA/National Centers for Environmental Information in Boulder, Colorado, and David W. Stahle of the University of Arkansas in Fayetteville.

The National Science Foundation, the U.S. Geological Survey and the Swiss National Science Foundation funded the research.

Trouet said, “There have been reconstructions of the drought conditions in California but no one’s looked at the snowpack in particular.”

After the extremely low snowpack levels in the Sierra Nevada were revealed in April, co-author Wahl wondered if it was possible to reconstruct the paleohistory of snowpack for those mountains.

Trouet thought the necessary data were available — so the team set to work.

Other researchers had already measured the width of tree rings for 1,505 blue oaks in California’s Central Valley from 33 different sites. Belmecheri and her colleagues put those measurements together as one long chronology, meaning the scientists had a blue oak tree-ring record that reached back reliably to the year 1405.

For those particular oaks (Quercus douglasii), the width of their annual rings reflects the winter precipitation they receive. Because the same storms that water the oaks also dump snow in the Sierra Nevada just to the west, the width of the blue oaks’ rings is a good proxy for snowpack in the Sierras, Trouet said.

Wahl had already published a reconstruction of central and southern California February-March temperatures from 1500 to 1980 that is independent of the blue oak tree-ring records.

Snowpack in the Sierras has been measured approximately since the 1930s, so the researchers checked their snowpack estimates from tree rings and the temperature reconstruction against actual snowpack measurements for 1930 to 1980.

The different measurements all lined up – when winter precipitation was lower and temperature was higher, snowpack was lower.

Peak snowpack is the measurement that hydrologists use to predict the amount of runoff that will occur in the summer, Trouet said.

The team’s next step, she said, is investigating and reconstructing the atmospheric circulation patterns that contribute to the California drought and the Sierra Nevada snowpack.

UNIVERSITY OF ARIZONA

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Virtual Interactive Environment of Ancient Egyptian Temple of Abu Simbel

The Great Temple of Ramesses II at Abu Simbel in Egypt has been digitally scanned to create a virtual interactive high-resolution environment.

Historical Document Details Martyrdom of Japanese Christian Retainers 400 Years Ago

In Japan, the suppression of Christianity increased from the end of the 16th century to the beginning of the 17th century, and many missionaries and Japanese believers were martyred during this period.

Archaeologists Discover Ornate Roman Domūs in Central Nîmes

Archaeologists conducting excavations in the French city of Nîmes have discovered the remains of two high status Roman domus (houses).

How Did Dogs Get to the Americas?

The history of dogs has been intertwined, since ancient times, with that of the humans who domesticated them.

First DNA Extracted from Modern, Ancient and Fossil Tropical Shells

In Wonderland, Alice drank a potion to shrink herself. In nature, some animal species shrink to escape the attention of human hunters, a process that takes from decades to millennia.

Medieval Containers Hint at Thriving Wine Trade in Islamic Sicily

Researchers at the University of York have found chemical residues of grapes in medieval containers indicating a prosperous wine trade in Islamic Sicily.

Kangaroo Painting Thought to be 17,300 Years Old

A two-metre-long painting of a kangaroo in Western Australia's Kimberley region has been identified as Australia's oldest intact rock painting.

Ani – The Abandoned Medieval City

Ani is a ruined medieval city, and the former capital of the Bagratid Armenian kingdom, located in the Eastern Anatolia region of the Kars province in present-day Turkey.

Popular stories

Ani – The Abandoned Medieval City

Ani is a ruined medieval city, and the former capital of the Bagratid Armenian kingdom, located in the Eastern Anatolia region of the Kars province in present-day Turkey.

Interactive Map of Earth’s Asteroid and Meteor Impact Craters

Across the history of our planet, around 190 terrestrial impact craters have been identified that still survive the Earth’s geological processes, with the most recent event occurring in 1947 at the Sikhote-Alin Mountains of south-eastern Russia.

The Sunken Town of Pavlopetri

Pavlopetri, also called Paulopetri, is a submerged ancient town, located between the islet of Pavlopetri and the Pounta coast of Laconia, on the Peloponnese peninsula in southern Greece.

Exploring the Avebury Stone Circle Landscape

The area was designated part of the Stonehenge, Avebury and Associated Sites by UNESCO in 1986, in recognition for one of the most architecturally sophisticated stone circles in the world, in addition to the rich Neolithic, and Bronze age remains found nearby, such as the West Kennet Avenue, Beckhampton Avenue, West Kennet Long Barrow, the Sanctuary, and Windmill Hill.