Search Results

You are looking at 1 - 3 of 3 items for :

  • Author or Editor: Connie A. Woodhouse x
  • Bulletin of the American Meteorological Society x
  • Refine by Access: All Content x
Clear All Modify Search
Connie A. Woodhouse
and
Jonathan T. Overpeck

Droughts are one of the most devastating natural hazards faced by the United States today. Severe droughts of the twentieth century have had large impacts on economies, society, and the environment, especially in the Great Plains. However, the instrumental record of the last 100 years contains only a limited subset of drought realizations. One must turn to the paleoclimatic record to examine the full range of past drought variability, including the range of magnitude and duration, and thus gain the improved understanding needed for society to anticipate and plan for droughts of the future. Historical documents, tree rings, archaeological remains, lake sediment, and geomorphic data make it clear that the droughts of the twentieth century, including those of the 1930s and 1950s, were eclipsed several times by droughts earlier in the last 2000 years, and as recently as the late sixteenth century. In general, some droughts prior to 1600 appear to be characterized by longer duration (i.e., multidecadal) and greater spatial extent than those of the twentieth century. The authors' assessment of the full range of past natural drought variability, deduced from a comprehensive review of the paleoclimatic literature, suggests that droughts more severe than those of the 1930s and 1950s are likely to occur in the future, a likelihood that might be exacerbated by greenhouse warming in the next century. Persistence conditions that lead to decadal-scale drought may be related to low-frequency variations, or base-state shifts, in both the Pacific and Atlantic Oceans, although more research is needed to understand the mechanisms of severe drought.

Full access
Connie A. Woodhouse
,
Jeffrey J. Lukas
, and
Peter M. Brown

A sustained mid-nineteenth-century drought in the western Great Plains has been indicated by a tree-ring analysis of trees flanking the western Great Plains, and in tree-ring reconstructions of drought and streamflow for eastern Colorado and the Colorado Front Range. The development of new tree-ring chronologies for the western Great Plains, in combination with existing chronologies, now enables a more detailed assessment of the spatial and temporal characteristics of this drought. The analysis of a set of drought-sensitive tree-ring chronologies ranging from the northwestern Great Plains to central New Mexico indicates a core area of drought from south-central Wyoming to northeastern New Mexico for the years 1845–56. Drought was particularly severe in the years 1845–48, 1851, and 1854–56, contracting and affecting smaller regions in intervening years. The impact of this drought on natural ecosystems and human activities is difficult to gauge because of the paucity of historical documents and the confounding effects of land use changes occurring over the same period. However, it is probable that this drought played a role in the decimation of bison herds in the second half of the nineteenth century. Were it to occur today, this relatively small but persistent drought would have significant impacts on the Colorado Front Range metropolitan area and the agricultural regions of eastern Colorado.

Full access
Thomas C. Peterson
,
Richard R. Heim Jr.
,
Robert Hirsch
,
Dale P. Kaiser
,
Harold Brooks
,
Noah S. Diffenbaugh
,
Randall M. Dole
,
Jason P. Giovannettone
,
Kristen Guirguis
,
Thomas R. Karl
,
Richard W. Katz
,
Kenneth Kunkel
,
Dennis Lettenmaier
,
Gregory J. McCabe
,
Christopher J. Paciorek
,
Karen R. Ryberg
,
Siegfried Schubert
,
Viviane B. S. Silva
,
Brooke C. Stewart
,
Aldo V. Vecchia
,
Gabriele Villarini
,
Russell S. Vose
,
John Walsh
,
Michael Wehner
,
David Wolock
,
Klaus Wolter
,
Connie A. Woodhouse
, and
Donald Wuebbles

Weather and climate extremes have been varying and changing on many different time scales. In recent decades, heat waves have generally become more frequent across the United States, while cold waves have been decreasing. While this is in keeping with expectations in a warming climate, it turns out that decadal variations in the number of U.S. heat and cold waves do not correlate well with the observed U.S. warming during the last century. Annual peak flow data reveal that river flooding trends on the century scale do not show uniform changes across the country. While flood magnitudes in the Southwest have been decreasing, flood magnitudes in the Northeast and north-central United States have been increasing. Confounding the analysis of trends in river flooding is multiyear and even multidecadal variability likely caused by both large-scale atmospheric circulation changes and basin-scale “memory” in the form of soil moisture. Droughts also have long-term trends as well as multiyear and decadal variability. Instrumental data indicate that the Dust Bowl of the 1930s and the drought in the 1950s were the most significant twentieth-century droughts in the United States, while tree ring data indicate that the megadroughts over the twelfth century exceeded anything in the twentieth century in both spatial extent and duration. The state of knowledge of the factors that cause heat waves, cold waves, floods, and drought to change is fairly good with heat waves being the best understood.

Full access