MAY 2003 AMERICAN METEOROLOGICAL SOCIETY | T he number and extent of wildfires in the western United States each season are driven by natural factors such as fuel availability, temperature, precipitation, wind, humidity, and the location of lightning strikes, as well as anthropogenic factors. It is well known that climate fluctuations significantly affect these natural factors, and thus the sev...

Increasingly, forest management goals include building or maintaining resistance and/or resilience to disturbances in the face of climate change. Although a multitude of descriptive definitions for resistance and resilience exist, to evaluate whether specific management activities (silviculture) are effective, prescriptive characterizations are necessary. We introduce a conceptual framework tha...

Recent bursts in the incidence of large wildfires worldwide have raised concerns about the influence climate change and humans might have on future fire activity. Comparatively little is known, however, about the relative importance of these factors in shaping global fire history. Here we use fire and climate modeling, combined with land cover and population estimates, to gain a better understa...

Increased forest density resulting from decades of fire exclusion is often perceived as the leading cause of historically aberrant, severe, contemporary wildfires and insect outbreaks documented in some fire-prone forests of the western United States. Based on this notion, current U.S. forest policy directs managers to reduce stand density and restore historical conditions in fire-excluded fore...

Given that they can burn for weeks or months, wildfires in temperate and boreal forests may become immense (eg., 10(0) - 10(4) km(2) ). However, during the period within which a large fire is 'active', not all days experience weather that is conducive to fire spread; indeed most of the spread occurs on a small proportion (e.g., 1 - 15 days) of not necessarily consecutive days during the active ...

Sudden oak death (SOD) is an emerging forest disease causing extensive tree mortality in coastal California forests. Recent California wildfires provided an opportunity to test a major assumption underlying discussions of SOD and land management: SOD mortality will increase fire severity. We examined prefire fuels from host species in a forest monitoring plot network in Big Sur, California (USA...

Risk analysis may be defined as the problem of estimating the probabilities of rare events and the magnitudes of associated damages. The topic unifies the environmental sciences. This paper considers risk analyses for earthquakes, wildfires and floods. The computation of insurance premiums is used to motivate and unite the work.

For certain risks, it is difficult to create and sustain broad public responses. The inconspicuousness of such risks is common in the absence of a major sudden and harmful event (Birkland, 1997). Recent damaging hurricanes and wildfires and the detection of sea-level rise for which the impacts can be reduced have prompted limited reaction among affected populations and public policymakers. For ...

The area burned in the North American boreal forest is controlled by the frequency of mid-tropospheric blocking highs that cause rapid fuel drying. Climate controls the area burned through changing the dynamics of large-scale teleconnection patterns (Pacific Decadal Oscillation/El Niño Southern Oscillation and Arctic Oscillation, PDO/ENSO and AO) that control the frequency of blocking highs ove...

Surging wildfires across the globe are contributing to escalating residential losses and have major social, economic, and ecological consequences. The highest losses in the U.S. occur in southern California, where nearly 1000 homes per year have been destroyed by wildfires since 2000. Wildfire risk reduction efforts focus primarily on fuel reduction and, to a lesser degree, on house characteris...