#Snowpack news: Accumulation curves are flattening, SW basins dropping #drought #aridification

Click on a thumbnail graphic to view a gallery of snowpack data from the NRCS.

And here’s the Western U.S. Interactive basin-filled map for December 17, 2018 from the NRCS.

Westwide basin-filled interactive map screen shot December 17, 2018.

#CRWUA2018: The effects of #ClimateChange loom over the #ColoradoRiver #aridification #COriver #ActOnClimate

From The Arizona Republic (Ian James):

With the water level in Lake Mead hovering near a point that would trigger a first-ever official shortage on the Colorado River, representatives of California, Arizona and Nevada are trying to wrap up a plan to prevent the water situation from spiraling into a major crisis.

The plan is formally called the Lower Basin Drought Contingency Plan. But at an annual Colorado River conference this week, many water managers stressed that it’s merely a stopgap plan to get the region through the next several years until 2026.

It might also rightly be called a temporary rejiggering of the rules, a quick fix to stave off a reckoning, or an initial step toward planning for a future with less water.

Looming over the negotiations is a long-term issue that is intensifying the strains on the river: climate change.

Some of the water wonks at the Colorado River Water Users Association conference called the proposed drought plan a temporary “bridge” solution, or a first step toward larger efforts to address the river’s pattern of over-allocation and adapt to climate change in the seven states that depend on the river.

“It will be a short-term solution to stave off the immediate impacts of the problems that we’re seeing,” said Cynthia Campbell, a water adviser for Phoenix. “Lake levels are going down just too fast.”

The idea is simply to stop the free-fall, she said, and provide a short window of time to begin to plan bigger steps…

The river has long been overused to supply farmlands and cities across the West. And during the past few decades, rising global temperatures have added to the strains.

The higher temperatures have shrunk the average snowpack in the mountains, reduced the flow of streams, and increased the amount of water that evaporates off the landscape.

Since 2000, the amount of water flowing in the Colorado River has dropped 19 percent below the average of the past century. Scientific research has found that about half the trend of decreasing runoff from 2000-2014 in the Upper Colorado River Basin was the result of unprecedented warming.

At this week’s meetings in Las Vegas, managers of water agencies said there is widespread recognition that the Colorado River system needs long-term adjustments to adapt as rising temperatures increasingly sap the river’s flow and lead to longer, more intense droughts…

Even with the reservoir’s dire situation hanging over the negotiations, finishing a drought plan has proven difficult.

Pressing for Arizona and California to sign on to the proposed three-state drought agreement, federal Bureau of Reclamation Commissioner Brenda Burman has given the states a deadline of Jan. 31.

She announced the deadline on Thursday, saying if the states fail to meet that deadline, the federal government will get involved and step in to prevent the reservoirs from falling to critically low levels.

Arizona’s top water officials say they’re optimistic they will be able to finish nailing down the details of agreements in the state to take a plan to the Legislature for approval in January.

This set of agreements would enable the state to join the larger three-state pact by spreading around the impacts of the water cutbacks, providing “mitigation” water to farmers in central Arizona, and paying compensation to other entities that would contribute water.

A few details remain to be worked out, including proposed funding to help farmers in Pinal County who face some of the biggest cutbacks in water deliveries.

Paul Orme, a lawyer who represents four agricultural irrigation districts in the area, said the growers are seeking $15 million to $20 million in funding from the state Legislature and the Central Arizona Project, as well as matching funds from the federal government.

That money would help drill between 40 and 50 new wells and pay for pumps and other infrastructure to help the farmers start to use more groundwater to partially replace the Colorado River water they’re going to lose…

Jennifer Pitt, the Colorado River program director for the National Audubon Society, said a great deal is at stake in the talks on the Drought Contingency Plan, because if the collaborative approach fails, decisions on how the river is managed could start to be made in more disruptive ways by the courts or federal officials.

“The most worrisome future is we don’t have the framework, we don’t have the collaboration, and the hydrology continues to tank, and it seems like the problems multiply,” Pitt said. “The Drought Contingency Plan is the key to avoiding really catastrophic problems for people and wildlife and birds in the Colorado River Basin.”

#Snowpack news: Long-term decline in the cards for the #West and worldwide #aridification #ActOnClimate

Credit: California Cooperative Snow Survey via YouTube

From The Arizona Daily Star (Tony Davis):

One of four studies discussed there, in which two University of Arizona researchers were co-authors, found that total snowpack in Colorado River Basin mountain ranges declined by 41 percent from 1982 to 2016. That’s the same rate as the overall decline that the study found in the worst-hit areas of the Western U.S. over the same period…

A second study found clear connections between declining snowpack in the West and increased wildfires in high-mountain forested areas dominated by trees such as ponderosa pine and Douglas fir.

A third study, looking globally, concludes that declining snowpack could put the water supplies of more than one-sixth of the world’s population at risk.

A fourth study found that the U.S. West’s snowpack seasons are being squeezed at both ends, with fall starting later and summer starting earlier.

“Our winters are getting sick,” that study’s author, Amato Evan of the Scripps Institution of Oceanography in La Jolla, California, said at Wednesday’s annual American Geophysical Union conference in Washington, D.C.

“If you gauge the health of winter on how normal snows in the mountains look, it’s reasonable to come to (that) conclusion,” said Evan, an associate professor of atmospheric and climate science, in a telephone interview Friday.

Evan and two other scientists who discussed their research at the conference, including UA professor of hydrology and atmospheric sciences Xubin Zeng, said they believe global warming and other forms of global climate change are at least partly responsible for the snowpack declines.

“We know the reason why — it has to do with global warming. It’s rising temperatures. It’s the only logical explanation for what is happening,” said Evan, an associate professor of atmospheric and climate science.

For one, he said, climate change is the most simple explanation for the declining snowpack, “and usually in questions like this the simplest answer is the correct one.” Second, there have been many climate model simulations forecasting snowpack declines over this century, and “more alarming, these are the changes we already see,” Evan said.

Warming temperature is an important factor in the decline of snowmass, which represents the weight and depth of snowpack, Zeng added. That’s because it decreases the percentage of precipitation that falls as snowfall and increases snow sublimation, a process in which snow transforms into ice and then into water vapor without first melting, he said.

Warming weather over the period Zeng studied, from 1982 to 2016, is linked by itself to about 25 percent of the total snowpack declines found in the study, concluded Zeng and his colleagues. The rest is due to changes in precipitation, in part caused by the fact that more precipitation today falls as rain instead of snow. Because an unknown amount of the precipitation change is also caused by warming, the total impact of warmer weather on snowpack declines actually exceeds 25 percent…

Details of the studies’ findings:

• Zeng and two other researchers concluded that snowpack had declined 41 percent between 1982 and 2016 on 13 percent of the West’s total land area.

The snow season was shortened by an average of 34 days over this period, on about 9 percent of the entire U.S.. Most of the declining area was concentrated in the West. The co-authors are Patrick Broxton, a UA associate research scientist in the School of Natural Resources and Environment, and Nicholas Dawson of the Idaho Power Company.

The researchers studied snowpack levels in areas of the U.S. broken into individual squares measuring 6.25 square miles. They looked at four kinds of snowpack data, including U.S. government-run monitoring stations. Their findings were just published in the journal Geophysical Research Letters.

• Evan said based on his study, the weight of the snowpack, commonly called snowmass, has dropped up to 50 percent at monitoring stations around the West from 1982 to 2018.

Generally, the snowpack seasons at high elevations are starting to resemble those at lower elevations, signaling declines at the more important high elevations, his study found. It was published in the Journal of Applied Meteorology and Climatology.

• Speaking of the wildfire study, still unpublished, author Donal O’Leary said, “We’re 95 percent confident there’s a significant relationship between wildfire and snowpack.”


Snowfall’s proportion of all annual precipitation is dropping more than 4 percent per decade in some key high mountain areas on the western Tibetan Plateau, middle-east Asia, northern Canada and on the Greenland Sea, he said. But it’s increasing about 2 percent every decade in oceans surrounding the Antarctic region.

It’s a wrap on TAP for 2018 – News on TAP

Revisit some of the places, people and projects we wrote about this year, with a countdown of the stories and videos you like the most.

Source: It’s a wrap on TAP for 2018 – News on TAP