• desJardins, M. L., , and Petersen R. A. , 1985: GEMPAK: A meteorological system for research and education. Preprints, First Int. Conf. on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Los Angeles, CA, Amer. Meteor. Soc., 313–319.

  • Grell, G. A., , Dudhia J. , , and Stauffer D. R. , 1995: A description of the fifth-generation Penn State/NCAR Mesoscale Model (MM5). NCAR Tech Note NCAR/TN-398+ STR, 117 pp.

  • Haines, D. A., 1988: A lower atmosphere severity index for wildland fires. Natl. Wea. Dig., 13 , 2. 2327.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Mahoney, E. A., , and Niziol T. A. , 1997: BUFKIT: A software application toolkit for predicting lake effect snow. Preprints, 13th Int. Conf. on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Long Beach, CA, Amer. Meteor. Soc., 388–391.

  • Niziol, T. A., , and Mahoney E. A. , 1997: The use of high resolution hourly soundings for the prediction of lake effect snow. Preprints, 13th Int. Conf. on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology, Long Beach, CA, Amer. Meteor. Soc., 92–95.

  • Walters, C. K., , Winkler J. A. , , Shadbolt R. P. , , van Ravensway J. , , and Bierly G. D. , 2008: A long-term climatology of southerly and northerly low-level jets for the central United States. Ann. Assoc. Amer. Geogr., in press.

    • Search Google Scholar
    • Export Citation
  • Winkler, J. A., , Potter B. E. , , Wilhelm D. F. , , Shadbolt R. P. , , Piromsopa K. , , and Bian X. , 2007: Climatological and statistical characteristics of the Haines index for North America. Int. J. Wildland Fire, 16 , 139152.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 55 55 30
PDF Downloads 34 34 24

Computing the Low-Elevation Variant of the Haines Index for Fire Weather Forecasts

View More View Less
  • 1 Pacific Northwest Research Station, USDA Forest Service, Seattle, Washington
  • 2 Department of Geography, Michigan State University, East Lansing, Michigan
  • 3 Northern Research Station, USDA Forest Service, East Lansing, Michigan
© Get Permissions
Restricted access

Abstract

The Haines index is used in wildfire forecasting and monitoring to evaluate the potential contributions of atmospheric stability and humidity to the behavior of plume-dominated wildfires. The index has three variants (“low,” “mid,” and “high”) that accommodate differences in surface elevation. As originally formulated, the low variant is calculated from temperature observations at the 950- and 850-hPa levels and humidity observations at 850 hPa. In the early 1990s the National Weather Service implemented a new mandatory level for radiosonde observations at 925 hPa. Following this change, measurements at 950 hPa became less frequent. An informal survey of several forecast offices found no formalized adjustment to the calculation of the low Haines index to take into account the nonavailability of 950-hPa measurements. Some sources continue to use 950-hPa temperature, usually interpolated from 925-hPa and surface temperatures, to calculate the low Haines index. Others directly substitute the 925-hPa temperature for the originally specified 950-hPa value. This study employs soundings from the central United States when both 950- and 925-hPa levels were available to investigate the impact of different calculation approaches on the resulting values of the low variant of the Haines index. Results show that direct substitution of 925-hPa temperature for the 950-hPa temperature can dramatically underestimate the potential wildfire severity compared with the original formulation of the Haines index. On the other hand, a low-elevation variant of the Haines index calculated from the interpolated 950-hPa temperature is usually in close agreement with the original formulation of the index.

Corresponding author address: Brian E. Potter, Pacific Wildland Fire Sciences Lab, 400 N. 34th St., Ste. 201, Seattle, WA 98103. Email: bpotter@fs.fed.us

Abstract

The Haines index is used in wildfire forecasting and monitoring to evaluate the potential contributions of atmospheric stability and humidity to the behavior of plume-dominated wildfires. The index has three variants (“low,” “mid,” and “high”) that accommodate differences in surface elevation. As originally formulated, the low variant is calculated from temperature observations at the 950- and 850-hPa levels and humidity observations at 850 hPa. In the early 1990s the National Weather Service implemented a new mandatory level for radiosonde observations at 925 hPa. Following this change, measurements at 950 hPa became less frequent. An informal survey of several forecast offices found no formalized adjustment to the calculation of the low Haines index to take into account the nonavailability of 950-hPa measurements. Some sources continue to use 950-hPa temperature, usually interpolated from 925-hPa and surface temperatures, to calculate the low Haines index. Others directly substitute the 925-hPa temperature for the originally specified 950-hPa value. This study employs soundings from the central United States when both 950- and 925-hPa levels were available to investigate the impact of different calculation approaches on the resulting values of the low variant of the Haines index. Results show that direct substitution of 925-hPa temperature for the 950-hPa temperature can dramatically underestimate the potential wildfire severity compared with the original formulation of the Haines index. On the other hand, a low-elevation variant of the Haines index calculated from the interpolated 950-hPa temperature is usually in close agreement with the original formulation of the index.

Corresponding author address: Brian E. Potter, Pacific Wildland Fire Sciences Lab, 400 N. 34th St., Ste. 201, Seattle, WA 98103. Email: bpotter@fs.fed.us

Save