Walker S. Ashley, Ph.D., CCM

Associate Professor, Meteorology Program, Department of Geography, Northern Illinois University

Certified Consulting Meteorologist (#668), StormForensics.com

 Steve Larson

219-D Davis Hall

Meteorology Program

Department of Geography

Northern Illinois University

DeKalb, IL  60115




Family Blog - Storm Chase Blog

Photographing a supercell west of Rapid City, SD on 1 June 2015. Live Altgeld Hall view. Click image for additional views.
I am an atmospheric scientist and physical geographer with interests in hazards and societal interactions, severe storms, and applied climatology and meteorology.  My current research focuses on 1) understanding how human exposure and vulnerability contributes to weather-related disasters, 2) how urbanization and other land covers/uses influence thunderstorm formation, 3) radar-based climatologies of organized thunderstorms, and 4) weather hazard impacts on transportation systems.  In the past, I have investigated the climatology and hazards of widespread and long-lived windstorms known as derechos, the rainfall patterns of convective complexes, the importance of increasing population and suburban sprawl on tornado vulnerability, and the geographies of weather-related fatalities in the U.S. 
Education: Other Affiliations:
Ph.D. (2005) University of Georgia

M.S. (2000) University of Nebraska

B.S. (1997) University of Georgia

A.S. (1995) Young Harris College

Faculty Associate, Institute for the Study of Environment, Sustainability, & Energy, NIU

Field and Experiential Learning, College of DuPage

Courses I teach or have taught: (next time offered)

Research Spotlight:

GEOG 105 Introduction to the Atmosphere

MET 291 Field Experience in Meteorology (Su '16)

MET 300 Meteorology

GEOG 303 Water Resources and the Environment (Su '16)

GEOG 306 Severe and Hazardous Weather (Su/F '16)

MET 360 Radar Meteorology (F '16)

GEOG 406/506 Natural Hazards and Environ. Risk (F '16)

MET 444/544 Mesoscale Meteorology (Sp '17)

GEOG 498C/790C Adv. Meteorological Applications

ESAS 1800 Introduction to Thunderstorm Lab (COD)


Journal publications: (Google Scholar citations)

Strader, S. M., T. Pingel, and W. S. Ashley, 2016: A Monte Carlo model for estimating tornado impacts. Meteorological Applications. DOI: 10.1002/met.1552 [PDF]

Ashley, W. S., and S. M. Strader, 2016: Recipe for disaster: How the dynamic ingredients of risk and exposure are changing the tornado disaster landscape. Bulletin of the American Meteorological Society. DOI 10.1175/ BAMS-D-15-00150.1 [PDF

Haberlie, A., W. S. Ashley, A. Fultz, and S. Eagan, 2016:  The effect of reservoirs on the climatology of warm-season thunderstorms in Southeast Texas, USA. International Journal of Climatology, 36, 18081820. [PDF]

Briley, L. J., W. S. Ashley, R. B. Rood, and A. Krmenec, 2016:  The role of meteorological processes in the description of uncertainty for climate change decision-making. Theoretical and Applied Climatology. DOI 10.1007/ s00704-015-1652-2. [PDF]

Roeder, W. P., B. H. Cummins, K. L. Cummins, R. L. Holle, and W. S. Ashley, 2015:  Lightning fatality risk map of the conterminous United States. Natural Hazards, 79, 1681-1692. [PDF]

Strader, S. M., and W. S. Ashley, 2015: The expanding bull's-eye effect. Weatherwise, 68, 23-29. [PDF; quick explanation of effect]

Ashley, W. S., S. Strader, D. Dziubla, and A. Haberlie, 2015:  Driving blind: Weather-related vision hazards and fatal motor vehicle crashes. Bulletin of the American Meteorological Society, 96, 755-778. [PDF]

Rosencrants, T., and W. S. Ashley, 2015:  Spatiotemporal analysis of tornado exposure in five U.S. metropolitan areas. Natural Hazards, 78, 121-140. [PDF]

Strader, S. M., W. S. Ashley, and J. Walker, 2015: Changes in volcanic hazard exposure in the Northwest USA from 1940 to 2100. Natural Hazards, 77, 1365-1392. [PDF]

Haberlie, A., W. S. Ashley, and T. Pingel, 2015:  The effect of urbanization on the climatology of thunderstorm initiation. Quarterly Journal of the Royal Meteorological Society, 141, 663-675. [PDF]

Strader, S., W. S. Ashley, A. Irizarry, and S. Hall, 2015: A climatology of tornado intensity assessments. Meteorological Applications, 22, 513-524. [PDF]

Ashley, W. S., S. Strader, T. Rosencrants, and A. J. Krmenec, 2014: Spatiotemporal changes in tornado hazard exposure: The case of the expanding bull's eye effect in Chicago, IL. Weather, Climate, and Society, 6, 175-193. [PDF; "Paper of Note" in BAMS; quick explanation of effect].

Strader, S., and W. S. Ashley, 2014: Cloud-to-ground lightning signatures of long-lived tornadic supercells in the Southeastern U.S. on 27-28 April 2011. Physical Geography, 35, 273-296. [PDF]

Stallins, J. A., J. Carpenter, M. Bentley, W. Ashley, and J. Mulholland, 2013: Weekend-weekday aerosols and geographic variability in cloud-to-ground lightning for the urban region of Atlanta, Georgia, USA. Regional Environmental Change. 13, 137-151. [PDF]

Ashley, W. S., M. L. Bentley, and J. A. Stallins, 2012: Urban-induced thunderstorm modification in the Southeast United States. Climatic Change, 113, 481-498. [PDF]

Bentley, M. L., J. A. Stallins, and W. S. Ashley, 2012: Synoptic environments favorable for urban-enhanced convection in Atlanta, Georgia. International Journal of Climatology, 32, 1287-1294. [PDF]

Gensini, V. A., and W. S. Ashley, 2011: Climatology of potentially severe convective environments from the North American regional reanalysis. Electronic Journal of Severe Storms Meteorology, 6(8), 1-40. [PDF]

Paulikas, M. J., and W. S. Ashley, 2011: Thunderstorm hazard vulnerability for the Atlanta, Georgia metropolitan region. Natural Hazards, 58, 1077-1092. [PDF]

Spencer, J. M., and W. S. Ashley, 2011: Avalanche fatalities in the western United States: A comparison of three databases. Natural Hazards, 58, 31-44. [PDF]

Black, A. W., and W. S. Ashley, 2011: The relationship between tornadic and nontornadic convective wind fatalities and warnings. Weather, Climate, and Society, 3, 31-47. [PDF]

Schoen, J., and W. S. Ashley, 2011: A climatology of fatal convective wind events by storm type. Weather and Forecasting, 26, 109-121. [PDF]

Black, A. W., and W. S. Ashley, 2010: Nontornadic convective wind fatalities in the United States. Natural Hazards, 54, 355-366. [PDF]

Gensini, V. A., and W. S. Ashley, 2010: An examination of rip current fatalities in the United States. Natural Hazards, 54, 159-175. [PDF; Formal comment and reply]

Bentley, M. L., W. S. Ashley, and J. A. Stallins, 2010: Climatological radar delineation of urban convection for Atlanta, Georgia. International Journal of Climatology, 30, 1589-1594. [PDF]

Bentley, M., T. Stallins, and W. Ashley, 2010: The Atlanta thunderstorm effect. Weatherwise, 63, 24-29. [PDF]

Ashley, W. S., and C. W. Gilson, 2009:  A reassessment of U.S. lightning mortality. Bulletin of the American Meteorological Society, 90, 15011518. [PDF]

Ashley, W. S., A. J. Krmenec, and R. Schwantes, 2008:  Vulnerability due to nocturnal tornadoes. Weather and Forecasting, 23, 795-807. [PDF; "Paper of Note" in BAMS]

Ashley, S. T., and W. S. Ashley, 2008:  Flood fatalities in the United States. Journal of Applied Meteorology and Climatology, 47, 805-818. [PDF]

Hall, S. G., and W. S. Ashley, 2008:  The effects of urban sprawl on the vulnerability to a significant tornado impact in northeastern Illinois. Natural Hazards Review, 9, 209-219. [abstract; email for PDF]

Ashley, S. T., and W. S. Ashley, 2008:  The storm morphology of deadly flooding events in the United States. International Journal of Climatology, 28, 493-503. [PDF]

Ashley, W. S., and A. W. Black, 2008:  Fatalities associated with nonconvective high-wind events in the United States. Journal of Applied Meteorology and Climatology, 47, 717-725. [PDF]

Ashley, W. S., 2007:  Spatial and temporal analysis of tornado fatalities in the United States: 1880-2005. Weather and Forecasting, 22, 1214-1228. [PDF]

Ashley, W. S., T. L. Mote, and M. L. Bentley, 2007:  An extensive episode of derecho-producing convective systems in the United States during May-June 1998: A multi-scale analysis and review.  Meteorological Applications, 14, 227-244. [PDF]

Suckling, P. W., and W. S. Ashley, 2006:  Spatial and temporal characteristics of tornado path direction. The Professional Geographer, 58, 20-38. [PDF]

Ashley, W. S., T. L. Mote, and M. L. Bentley, 2005:  On the episodic nature of derecho-producing convective systems in the United States. International Journal of Climatology, 25, 1915-1932. [PDF]

Ashley, W. S., and T. L. Mote, 2005:  Derecho hazards in the United States. Bulletin of the American Meteorological Society, 86, 1577-1592. [PDF]

Ashley, W. S., T. L. Mote, P. G. Dixon, S. L. Trotter, J. D. Durkee, E. J. Powell, and A. J. Grundstein, 2003:  Distribution of mesoscale convective complex rainfall in the United States. Monthly Weather Review, 131, 3003-3017. [PDF]

Other selected publications:

Ashley, W. S., and V. Gensini, 2014: Weather, extreme weather, and extreme storms. The International Encyclopedia of Geography. Richardson et al. Eds., Wiley-Blackwell. [accepted]

Ashley, W. S., S. M. Strader, T. Rosencrants, and A. J. Krmenec, 2014: Is the Expanding Bull's Eye Effect leading to greater and more frequent weather disasters? Paper of Note. Bulletin of the American Meteorological Society. 95, 510-511. [PDF]

Ashley, W. S., P. Young, and F. Schwantes, 2013: An inexpensive webcam system for capturing live skyscapes and time-lapse cloudscapes. Preprints, 22nd Symposium on Education, American Meteorological Society. 4 pp. [PDF]

Fuhrmann, C., and W. S. Ashley, 2010: Lightning. Encyclopedia of Geography. B. Warf Ed., SAGE Publications, 1780-1784.

Fuhrmann, C., and W. S. Ashley, 2006: Cloud-to-ground lightning characteristics of derecho-producing convective systems in the central and southern Great Plains. Preprints, 23rd Annual Conference on Severe Local Storms, American Meteorological Society. 6 pp. [PDF]

Funded grants:

National Science Foundation, Geography & Regional Science Program and Physical & Dynamic Meteorology Program, Climatological and Event-based Radar Delineation of UHI Convection for Urban Corridors within the Southeastern U.S., co-PI with M. L. Bentley and J. A. Stallins, 2007-2012.

NIU Undergraduate Research and Apprenticeship Program. Spring 2006, Fall 2006-Spring 2007, Fall 2007-Spring 2008, Fall 2008-Spring 2009, Fall 2009-Spring 2010, Fall 2010-Spring 2011, Fall 2011-Spring 2012, Fall 2012-Spring 2013, Fall 2013-Spring 2014, Fall 2014-Spring 2015.

NIU Research and Artistry Grant. Summer 2006, Summer 2008, Summer 2014.

NIU Undergraduate Research Assistantship. Summer 2014, Spring 2015.

NIU Student Engagement Fund. Summer 2015, Fall 2015.

NIU Great Journeys Assistantship. Fall 2014-Spring 2015, Fall 2015-Spring 2016.

Former and current graduate students:
Advisor/Major Professor: Soren Hall, M.S., 2006 (U.S. Army Corps of Engineers); Alan Black, M.S., 2008 (IIHR-Hydroscience & Engineering, University of Iowa); Monica Zappa, M.S., 2009 (Gilbert F. White Award; Osmar Racing); Chris Gilson, M.S., 2009 (KRQE); Joe Schoen, M.S., 2009 (Geneva High School); Jeremy Spencer, M.S., 2009 (Lecturer, University of Akron); Marius Paulikas, M.S., 2010 (Instructor, Bowling Green State University); Victor Gensini, M.S., 2010 (Associate Professor, College of DuPage); Andrew King, M.S., 2011 (Lanworth, Inc); Laura Briley, M.S., 2012 (Great Lakes Integrated Sciences + Assessments Center); Troy Rosencrants, M.S., 2013 (Geographic Information Systems Center, University of Michigan-Flint); Kristina Rohrbach, M.S., 2013 (Gilbert F. White Award; City of St. Charles); Andrew Fultz, M.S., 2015 (Aerotec); Shane Eagan, M.S. student (Murray & Trettel); Stephen Strader, Ph.D. candidate (M.S., NIU, 2012; NIU Outstanding Thesis Award); Alex Haberlie, Ph.D. student (M.S., NIU, 2014; NIU Outstanding Thesis Award); Ashley Irizarry, M.S. student; Alex Ferguson, M.S. student; Robert Fritzen, M.S. student; Hannah Eboh, M.S. student.

Committee Member: Lauren Lee, M.S., 2006 (GIS Analyst, Carroll County, IL); Dustin Oltman, M.S., 2007 (Aon Benfield); Cameron Lee, M.S., 2010 (Ph.D. student, Kent State Univ.); Tom Walsh, M.S, 2010 (Lanworth, Inc); Ian Chang, M.S., 2012 (Ph.D. student, University of Alabama-Huntsville ); Rick DiMaio, M.S., 2013 (Professor, Lewis University); Laura Skelly, M.S., 2013 (Corn Mazes America); Adam Dawson, M.S., 2013 (Aon Benfield); Alan Marinaro, M.S., 2015 (MDA Information Systems); Stefanie Pansch, M.S. student; Casey Heuer, M.S. student.


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What is a chubasco? A violent squall with thunder and lightning, encountered during the rainy season along the west coast of Central America.