Forest fires continue to burn in Colorado. Western Colorado is in its 3rd year of drought. Despite the late spring snow and rain and the apparent “greeness” of the landscape the forests are quite dry (June 22, 2013). Since 1980 snowpacks have declined through out the Rocky Mts. Computer modeling demonstrates that the 2 degree temperature increase over that period has been a major contributor to this trend, which increase the risk of wild fires.
3. From US Forest Service: “Effects of Climatic Variability and Change on Forest Ecosystems: A Comprehensive Science Synthesis for the US Forest Secton”, Dec 2012, 282 page James M. Vose, David L. Peterson, and Toral Patel-Weynand, Editors.This report is a scientific assessment of the current condition and likely future condition of forest resources in the UnitedStates relative to climatic variability and change. It serves as the U.S. Forest Service forest sector technical report for theNational Climate Assessment and includes descriptions of key regional issues and examples of a risk-based framework for assessing climate-change effects.
PAGE 201: CONCLUSIONS: “A warmer climate will increase the area burned by wildfire and the area affected by bark beetles and other insects. These two factors, individually, in combination, and as components of broader stress complexes, may lead to permanently altered species composition, distribution of forest age and structure, and spatial patterns across large landscapes.”
PAGE 8: “(From) 1971 to 2000 large effects have been seen with less than 1 °C warming (~2F) over the past 30 years. For example, snowpack is melting earlier in the spring, forest fires are becoming larger, bark beetles are moving higher in elevation and attacking species that were climatically protected in the past, bark beetle and other insect outbreaks have become larger and more frequent without very cold winters to stop them, and drought has killed trees in the drier regions of tree species’ ranges.”
Snow cover in the Rocky Mountains has declined by 20 percent over the past three decades, a study* published in May 2013 shows. Coupled with earlier and faster snowmelt, the dwindling snowpack poses problems for ecosystem health and watershed management in the western states.
Scientists used monthly data recorded from 1895 to 2011 to quantify the influences of winter and spring temperatures and precipitation on snowpack trends and variations in the region. Since 1980, snowpacks have decline throughout the Rocky Mountains, and most severely in the northern Rockies. Modeling demonstrates how temperature has been the major driver of this trend, which increases the risk of floods and wildfires.
*The study was conducted by U.S. Geological Survey scientists and published in Geophysical Research Letters a journal of the American Geophysical Union. GEOPHYSICAL RESEARCH LETTERS, VOL. 40, 1811–1816, doi:10.1002/grl.50424, 2013
from GPL abstract: The post-1980, synchronous snow
decline reduced snow cover at low to middle elevations by
~20% and partly explains earlier and reduced streamﬂow and
both longer and more active ﬁre seasons. Climatologies of
Rocky Mountain snowpack are shown to be seasonally and
regionally complex, with Paciﬁc decadal variability
positively reinforcing the anthropogenic warming trend.
Citation: Pederson, G. T., J. L. Betancourt, and G. J. McCabe
(2013), Regional patterns and proximal causes of the recent
snowpack decline in the Rocky Mountains,
Corresponding author: G. T. Pederson, U.S. Geological Survey,
Northern Rocky Mountain Science Center, 2727 University Way (Suite 2),
Fuels and Fire Behavior Advisory
Western Slope of Colorado
Subject: Western Colorado is in the third year of drought. The situation is predicted to persist or intensify
through July. There is increased risk of large fire development and intense fire behavior. Dry, heavy fuels at
higher elevations could pose a greater risk of active fire behavior.
Discussion: The wet spring pattern that occurred during April and May has provided a brief reprieve. Live
and dead fuel moistures are quickly returning to a condition that will support large fire growth.
Forecasts do not offer the prospect of live or dead fuels conditions improving through July.
Difference from normal conditions: Fuels are described by fire managers as being deceptively green.
The visual greenness being observed can lessen the sense of fire potential. Live fuels, which had shown
some improvement from late spring precipitation, are drying. On the Western Slope of Colorado, 100FM fuels
are setting historically low values for the date, nearing the 3rd percentile, and moving into the range
associated with historic large fires. Long-term drying has made large, higher elevation fuels, available as well.