Category Archives: Variability, Weather, & Extreme Events

What Does Climate Change Mean for Flooding in the Columbia River Basin?

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By Karen Hills

Aerial view of farms along a river with flood waters in fields and around buildings

Figure 1. The Pacific Northwest was hit by an historic flood in February 1996. Corps dams were put to the test and held back as much of the flood waters as possible, but too much rain fell in the valley below the dam. As a result, many communities in western Oregon felt the impacts of the flood waters. Photo: Portland Corps under CC BY 2.0.

Previous posts on AgClimate.net have focused on research related to anticipated climate change impacts on water availability and timing of available irrigation water in the Columbia River Basin, given the concern with having sufficient water to support the range of uses in the region. But is too little water the only concern? Laura Queen of the Oregon State University Climate Change Research Institute is the author of a recently published paper titled “Ubiquitous increases in flood magnitude in the Columbia River Basin under climate change.” Queen and her colleagues explain how in systems dominated by snowmelt, as is common in the Pacific Northwest, observational studies have shown consistent changes toward earlier spring streamflow and lower summer streamflow. This change has important implications for water users in the region. Less frequently discussed are the anticipated impacts on flooding (Figure 1), which is second only to fire in federal disaster declarations brought about by natural disasters in the Pacific Northwest. Continue reading →

Check it out: Putting Oregon’s September Fires in Past—and Future—Context

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By Sonia A. Hall

Roadside Fire Danger sign showing "Extreme" danger

Fire danger was considered extreme on and around Labor Day 2020. Close to the Beachie Fire in Marion County, OR. Photo: Oregon Department of Transportation, under CC BY 2.0.

Most of us probably agree that 2020 was an unprecedented year in many ways. Much of the western U.S. will remember 2020 for, among other things, the extensive fires that burned across many states. One of those states is Oregon, where climatic and weather conditions converged during Labor Day to enable large fires across the western slopes of the Cascades. Check out climatologists John Abatzoglou, David Rupp, and Larry O’Neill’s article titled Climate Enabling Conditions and Drivers of the Western Oregon Wildfires of 2020. They discuss the conditions that enabled these fires, and provide some historical context for their occurrence. Spoiler alert: their concluding paragraph states that “The best science available indicates that the conditions that enable large wildfires and wildfire seasons will become more common as a result of climate change and past and current land management and land use.” Many communities are heeding this information and working towards reducing vulnerabilities and improving resilience, to better deal with future fires. Please share with us and AgClimate.net readers those tools, resources and information you have found useful in such efforts.  You can comment on this post, or contact us via the Ask A Question tab.

A Review of Climate Change Research in the Columbia River Basin: Missing the Mark on Agriculture

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By Paris Edwards

Stream through an alpine meadow, with a snowcapped mountain in the background

Headwater streams originate in mountainous areas and add critical snowmelt to summer and early fall stream flows. Slow and steady melt off of winter snowpack provides water during the dry season when crops need it most. Photo by Picasa, Wikimedia Commons under CC BY-SA 3.0.

Our understanding of regional climate change effects today will be used to inform management, policy, and the new scientific endeavors of tomorrow. With this in mind, a team of doctoral students from the Water Resources Department at the University of Idaho in Moscow carried out a systematic review of all peer-reviewed studies through 2016 (550 of them) related to climate change in headwater regions of the Columbia River Basin. The purpose of the review was to explore what aspects of climate change impacts on water availability have been well studied, and where additional research is still needed (Marshall et al. 2020). We focused on mountain headwater regions because these critical water-generating areas are vulnerable to increasingly warm winter temperatures that contribute to snowpack losses and increased variability in the timing and volume of water available for multiple uses. Water availability supports values we care about and communities in our region, including irrigation; the future of irrigated agriculture in the Basin depends on water, and at least 20% of surface supply in the Basin is generated from melted snow. Continue reading →

Hot, Dry Summers Take a Toll on Trees in Western Washington

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By Patrick Shults, Washington State University Extension

Tops of two conifer trees, one showing dead branches at the very top, with green canopy below

Western redcedar with a dead top as a result of drought stress. Photo: Patrick Shults, WSU Extension.

The coastal Pacific Northwest is home to some of the best tree-growing conditions in the world.  Fertile soils, plenty of rain, mild temperatures, and short dry seasons allow trees to pack on solid growth each year.  These conditions also give them a significant advantage in protecting themselves from insects and disease with tactics like pitching sap to flush out bark beetles, isolating roots infected with fungus, and compartmentalizing wounds.  However, these defenses are only possible when trees can avoid environmental stressors and, given a changing climate, certain stressors are expected to become more frequent.

Trees in this area have evolved to handle an annual dry season and, generally, mild temperatures during that time ensure they don’t suffer too much stress.  However, in the last decade the coastal Pacific Northwest has experienced unusually stressful conditions.  The summers of 2015, 2017, and 2018, for instance, were very dry and also particularly hot, which worsens moisture stress in trees.  While it is difficult to attribute any given year to climate change, climate modeling suggests hotter summers like these may be a new normal, and a drive down I-5 in western Washington will show many trees have already paid a price. Continue reading →

Acting to Prepare for Severe Droughts in the Yakima River Basin

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By Mengqi Zhao, recent PhD graduate, Washington State University

Collage of three photos, with plants in greenhouse, a dry pond with no vegetation, and a sprinkler over a crop, close up

Figure 1. Under low water availability conditions, the reliability of irrigation systems can be enhanced through strategies that improve water supply when it is needed or reduce water demand. Examples include greenhouses (left), aquifer recharge (recharge pond, top right), and irrigation technology (bottom right). Photos: Mengqi Zhao (greenhouse and pond) and Kay Ledbetter, Texas A&M AgriLife Research, under CC BY-NC-ND 2.0 (sprinkler).

For more than fifty years, individuals and organizations in the Yakima River Basin (YRB) have been working toward improving water availability, especially for agriculture. The mismatch between rainfall (and snowmelt) timing and the irrigation season has focused these efforts on strategies for increasing water storage. However, farmers frequently encounter insufficient irrigation water supply and large demands from agricultural activities, resulting in prorationing across irrigation districts during every severe drought of record since 1970s. In the Pacific Northwest, projected water scarcity situations under future climate change scenarios could increase to 68% of years in the 2080s if no actions are taken, compared to only 14% of years on average historically (Vano et al., 2010).

Facing such frequent low water availability conditions, what methods can improve the reliability of irrigation systems? How might people’s decisions on adopting those methods affect system vulnerability to droughts? The fundamental solutions to these questions rely on strategies that either improve water supply when it is needed or reduce water demand. Continue reading →

The Need for Flexibility when Managing Grazing

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Matthew C. Reeves, U.S. Forest Service, Rocky Mountain Research Station

Grassy, green hillslope with some shrubs scattered around

Forage variability is expected to increase even further in the future, enhancing the need for flexibility in managing grazing on rangelands in the Pacific Northwest. Photo: Darrell Kilgore.

The amount of annual net primary production on rangelands forms the forage base upon which livelihoods and billions of dollars of commerce depend. Land managers and livestock producers in the Pacific Northwest deal with high year-to-year variations in net primary production, which often varies 40% between years due to changes in the amount of precipitation from one year to the next. And in the future, it is widely expected that climate change will lead to further increases in year-to-year variability, creating both challenges and opportunities for ranchers in the region. We therefore need to understand the longer-term changes in how net primary production and resulting forage production will vary, so we can explore new options that provide increased flexibility to ranchers and managers. Continue reading →

Dry Farming Gains Ground in the Northwest

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By Paris Edwards, USDA Northwest Climate Hub and Amy Garrett, Oregon State University Extension

Rows of densely covered vegetable crops, with a row of trees in the background

Dry farming trial at the Oregon State University Oak Creek Center for Urban Horticulture. Photo: Amy Garrett, taken on July 27th, 2020.

In parts of the maritime Pacific Northwest, climate conditions work well for dry farming, a set of soil preparation and management techniques that allow for growing food with little to no supplemental water. Dry farming has a long history of practice in the West, but a recent resurgence in popularity can be linked to water access challenges, drought, and uncertain future climate conditions. Dry farming fruits and vegetables requires a set of techniques that are evolving as the global network and local community of experts continues to expand and innovate together. So how is the reemergence of dry farming in the Northwest unfolding, and what does it have to offer growers and consumers? Continue reading →

Are There More Multiyear Snow Droughts in Our Future?

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By Adrienne Marshall

Hiker in a high elevation area, with a small lake and ridges with patchy snow in the background

Late May in the Sierra Nevadas in 2015, a low snowpack year that enabled spring recreation in the high country. Photo: Darren Bagnall.

As an environmental scientist, I’ve done plenty of hiking in the western U.S., always with a map, water bottle and list of water sources. In dry areas it’s always smart to ration water until you get to a new source. Sometimes a stream has dried up for the season, or a pond is too scummy to drink from, so your supply has to stretch further than planned. On one memorable hike, I found that a water source was dry. The next one, three miles later, was dry too. And the one after that had a dead bear carcass in it. While one dry water source was tolerable, several in a row created a serious problem.

Something similar is happening to snow resources in the western United States. Scientists have long known that the warming temperatures associated with climate change are diminishing the region’s snowpack, with more precipitation falling as rain, rather than snow. That’s a problem because snowpack is a critical resource, acting as a natural reservoir that stores winter precipitation. Are we likely to face several low snowpack years in a row? Continue reading →

How Can Long-Term Water Storage Management Mitigate Problems in an Era of Water Resource Deficits?

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Mengqi Zhao, Ph.D. Candidate, Department of Civil and Environmental Engineering, Washington State University

Set of containment structures filled with water, an aquifer recharge area

Figure 1. Managed Aquifer Recharge, like this example for the Merti aquifer shared between Kenya and Somalia, can help provide additional water in periods of water scarcity. The photo is from the Intergovernmental Authority on Development. (IGAD).

The 2015 drought caused more than $700 million in economic losses across Washington State. Even with current water storage management, both in places where rivers, lakes, and reservoirs generally provide sufficient water and in places where aquifers are the most stable water resource across seasons, extreme drought still impacted our economy. While droughts may impact different places with varying intensity, the risk of long-term water scarcity is greater when aquifers provide water today at the expense of tomorrow’s supply. As the region faces population increases and increasing competition for water resources to provide environmental value and economic value, the risk may increase further. So what water management options can help us mitigate the impacts of drought in the future?

In our region, we are experienced in using surface reservoirs as buffers between the naturally variable water cycle and the relatively more consistent agricultural water demand. The less visible buffer underground has often been ignored. Yet interest is growing, as aquifers may also be a useful reservoir over the long term, if managed sustainably. Our research team is evaluating managed aquifer recharge (MAR), an approach that stores water in the aquifer during the snowmelt season, allowing users to pump it for irrigation during periods of water scarcity (Figure 1). We have been asking questions about how to recharge aquifer systems to optimally achieve both short-term usage and long-term water supply sustainability. Imagine that the amount of water recharged into the aquifer becomes your future available MAR entitlement to pump up when needed. The more water that recharges the aquifer, the more effective the MAR will be in mitigating drought impacts. We are interested in answering specific questions, such as ‘What timing of recharge and infiltration area would have been needed for managed aquifer recharge to provide an effective buffer against the 2015 drought?’ or ‘How effective is managed aquifer recharge for maintaining sustainable water supply during single-year drought or even multi-year droughts?’ Continue reading →

Check it out: Using the Climate Toolbox to Explain This Winter’s Snowpack Dynamics

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By Sonia A. Hall

Skier on a slope with deep powder, and trees on either side

Snowpack in the Cascade Mountains contributed to the somewhat unusual patterns we have seen in this winter’s snowpack. Photo: Peter Stevens under CC BY 2.0.

You may have seen announcements or other Check It Out articles we have posted on AgClimate.net that speak about the Climate Toolbox. This online resource is a collection of tools for addressing questions relating to agriculture, climate, fire conditions, and water developed at the University of Idaho. Oriana Chegwidden, a research scientist and PhD student in Civil and Environmental Engineering at the University of Washington, has recently written an article in the Climate CIRCulator that showcases how you might use the wealth of climate data that the Climate Toolbox synthesizes. She describes the somewhat unusual patterns we have seen in this winter’s snowpack, and what we might see through the rest of the season, running through a few of the Climate Toolbox maps as examples. In this way her article both gives detail and depth on this year’s snowpack dynamics, and provides a neat example of how this tool can be used. So check it out!