Category Archives: Variability, Weather, & Extreme Events

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!

We Need to Know if Stormwater Runoff in Near-Urban Agricultural Areas Impacts Soil or Plant Health

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By Jordan Jobe, Master of Environmental Management,  Washington State University-Puyallup

view of field by a road, with houses and buildings in the far background

The Puyallup Watershed in Washington State has dozens of family farms pinned between townhomes, traffic-dense roads, commuter train tracks, and industrial sites. Photo: Jordan Jobe.

As farmland in the Puyallup Watershed increasingly finds itself pinned between townhomes, traffic-dense roads, commuter train tracks, and industrial sites, it seems important to be aware of unintended impacts on agricultural viability. Today, the Puyallup River floodplain is used in a variety of ways, including residential housing, commercial and industrial uses, salmon habitat (including restoration and mitigation sites), and agricultural production. The floodplain has fertile, rich soil and is home to dozens of farms growing mixed vegetable row crops.

The Puyallup Watershed has around 14,000 acres of active agricultural production, including dozens of family farms in these fertile floodplain areas. However, as land prices skyrocket and development occurs, farmers often have to face difficult decisions about what to do with their land. Continue reading →

Check it out: “Skeptical Science” a Climate Science Resource for Extension Professionals

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By Chris Schnepf

Screen shot showing a list of 6 climate myths and "what the science says" response links.

The Skeptical Science website outlines nearly 200 common climate change myths, and summarizes scientific responses to each assertion, with links to cited research. Screen shot from https://skepticalscience.com/argument.php.

One of the biggest challenges facing extension professionals is how to address climate change, especially in the context of people asking questions or making assertions that challenge climate science. Many of these questions have some kind of “gotcha” premise or multi-layered assumptions which must be pulled out and addressed individually to respond.

These kinds of questions are difficult to deal with even on comparatively simple topics like managing a specific insect pest, but they are even more challenging in an arena as complex as climate change, especially since many extension educators do not have as much depth of training as they do in a specific discipline such as agronomy or forestry.  Continue reading →

Climate Adaptation: USDA Programs and Resources That Can Help

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By Paris Edwards, Haley Case-Scott, and Holly R. Prendeville, USDA Northwest Climate Hub

Rural landscape showing flooded fields, roads, and buildings

Figure 1. Drone photo of highway 34 closed near Corvallis, Oregon. 11 April, 2019. Photo: Oregon Department of Transportation under CC BY 2.0.

Whether you are reading the news or talking with your community, the number of stories about how climate change and its impacts affect daily life and business across the Northwest, the United States, and the world is growing. Recently, there have been a number of extreme weather events in the Northwest. In January 2019, central Washington was hit by a blizzard that devastated dairy farmers. In April, Oregon rivers, including the Willamette and Santiam, reached flood stages that caused debris flows, pollution, and lead to evacuations throughout Eugene (Figure 1). Boise, Idaho experienced record rainfall between January and May this year, which contributed to grass growth throughout the region and raised concerns about an increase in wildland fire potential. Fortunately, cooler temperatures prevailed, resulting in a relatively mild wildland fire season and a break from smoke for Idaho, Oregon and Washington. Although it isn’t always clear if a particular event is due to climate change, more frequent and extreme weather occurrences are expected. These current events, alongside disasters of the recent past, highlight what we can expect to see more often in the future, given the predicted increases in flooding, extreme heat events, drought, and wildfire. Such events give added urgency to the need for efforts to reduce negative impacts and support resilience (Jay et al., 2019). Yet it is challenging for producers and natural resource managers to find the resources they need to do so. Continue reading →