Weather Effects
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Because ecosystems are complex, ecological drought definitions currently are more conceptual than operational (e.g., “an episodic deficit in water availability that drives ecosystems beyond thresholds of vulnerability, impacts ecosystem services, and triggers feedbacks in natural and/or human systems”). Identification of drought and drought characteristics depends on the drought definition and metric being sought.
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Fire is an essential component in restoring and maintaining a healthy forest. However, historic land use and decades of fire suppression has excluded fire from millions of forested hectares across much of the western United States, including the Grand Canyon National Park. Forest restoration at the Grand Canyon aims to reduce wildfire vulnerability by applying fire to diversify or remove forest vegetation. However, the cost, complexity, and concerns associated with managing fire for resource benefit requires that fire managers utilize and implement locally-relevant, science-based knowledge to strategically identify when and where to use fire to produce the greatest benefits. This research specifically addresses the National Park Service, Fire Management Leadership Board priority area of: Research that assists in removing stumbling blocks and hurdles for implementing fuels treatments and managing wildfires for resource objectives. We observed fire behavior in the Grand Canyon in conjunction with topographic variation and weather conditions to provide thresholds that affect fire severity and spread that may be beneficial or incompatible with multiple resource objectives. In doing so, we also developed customized tools that can be used to assist with fire management planning and quickly identifying conditions likely to affect fire behavior at Grand Canyon National Park.
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Historic drought conditions across the western United States continue to rapidly worsen and expand with over 80% of the West now in drought, according to the U.S. Drought Monitor. Widespread impacts are being felt. To provide the latest information on drought conditions across the Southwest, California, Pacific Northwest, and the Missouri River Basin, as well as the serious impacts on diverse sectors of the economy, NIDIS is joining with our federal, state, tribal, and local partners to host a drought webinar specifically for western communities.
The webinar will include an update on the current drought situation and outlook, an overview of wildland fire conditions and outlook, and will feature perspectives from those on the ground who are responding to worsening drought conditions. Key discussions will include a summary of past and current conditions in terms of many climate variables like snowpack, temperatures, precipitation, soil moisture, etc.; as well as potential and ongoing impacts from drought across sectors (e.g., agriculture, water resources, recreation, etc.).
WindNinja, a tool developed by RMRS scientists, delivers high-resolution wind predictions within seconds for emergency fire responders making on-the-ground decisions. The program computes spatially-varying wind fields to help predict winds at small scales in complex terrain. These predictions are extremely important in fire-prone landscapes where local changes in the near-surface wind are not predicted well by either operational weather models or expert judgment but are extremely important for accurate fire behavior predictions.
Because three key thresholds must be crossed all at once for a wildfire to start, avoiding just one of these thresholds─ ignitions, drought, or continuous fuels (Fig.1)─ could significantly reduce the likelihood of wildfire. As climate change makes fire weather more common everywhere, managing ignitions where wind is problematic and managing fuels where drought is problematic will help to keep stochastic, out-of-regime fires contained. Where fire management tools won’t help, a fire danger zone should be designated to reduce human activity and development, much like volcano or flooding zone designations.
Webinar registration, register by 7/7
Do you use (or *wish* you could use) soil moisture data or maps to support your decision making, advising, or other work activities? Do you want to share your opinions on which soil moisture datasets, maps, and tools are needed to better inform drought, flood, or other natural resource issues?
In July, the National Coordinated Soil Moisture Monitoring Network is hosting two listening sessions for soil moisture end users to share their thoughts, wish lists, and out-of-the-box ideas about what types of soil moisture products would best serve them. Target participants include federal, regional, and state program staff; state climatologists; water resource managers; extension agents; and any others who are interested in products derived from soil moisture data, whether it be from in situ mesonets, modeling outputs, and/or satellite retrievals.
Participants can choose either this session (July 13) or an identical session on July 22, both at 1 – 3 p.m. ET. Please register by Wednesday, July 7.
Webinar recording.
The Pacific Northwest Drought Early Warning System (PNW DEWS) Drought & Climate Outlook Webinar is part of a series of regular drought and climate outlook webinars designed to provide stakeholders and other interested parties in the region with timely information on current drought status and impacts, as well as a preview of current and developing climatic events (i.e. El Niño and La Niña).
Climatology Research Professor Tim Brown, also director of the Western Regional Climate Center, will discuss how weather and climate influence fire in Nevada.
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Widespread, rapid aspen (Populus tremuloides) mortality since the beginning of the 21st century, sometimes called sudden aspen decline (SAD), has been documented in many locations across North America, but it has been particularly pronounced in the southwestern U.S. We investigated the relationship between aspen growth, mortality, and climate across three forest types in northern Arizona using crossdated tree-ring samples from 126 live and 132 dead aspen. Aspen growth was negatively correlated with warm temperatures and positively associated with higher precipitation. Using survival analysis techniques to investigate the links between aspen mortality, tree traits, and climatic conditions, we found that tree traits played a larger role in mortality risk than climate factors. Trees with larger diameters, older trees, and trees with faster growth rates over the past 50 years had a reduced risk of mortality. Management actions aimed at maintaining the most vigorous, fastest growing aspen in the region could help mitigate the impacts of a warmer, drier future.
Webinar recording.
Drought can exacerbate wildfire frequency, intensity, and severity. This webinar explores wildfire management approaches based on ecological principles, including those that embed traditional ecological knowledge.
Presenters: Dr. Jeremy Littell, Research Ecologist, Alaska Climate Adaptation Science Center, USGS
Bill Tripp, Deputy Director of Eco-Cultural Revitalization, Department of Natural Resources, Karuk Tribe