Comparing the Haines Index with the Hot-Dry-Windy Index

In a comment on the earlier post about the Hot-Dry-Windy Index (HDW), Brian Potter, a research meteorologist with the U.S. Forest Service, offered to provide some preliminary results looking at how HDW performed during the 2017 Chetco Bar Fire in Oregon, as well as how the Haines index performed during that fire.

The HDW is a new tool developed for firefighters to predict weather conditions which can affect the spread of wildfires. It is described as being very simple and only considers the atmospheric factors of heat, moisture, and wind.

Mr. Potter has provided three figures showing the weather indices computed from the National Weather Service’s NAM model analyses. Because they use a different model from the HDW website, he does not have historic percentile values for HDW, but they are illustrative, nonetheless. These are preliminary data and have not been through peer review or evaluation.

Here is a graph of HDW values compared to growth on the Chetco Bar Fire:hot dry windy index fire growth

Here are the Haines Index values for the mid-elevation version of the Index:

Haines index fire growth

And the high elevation version of the Haines Index:

Haines index fire growth

Mr. Potter said he has some thoughts about the graphs, but is interested in hearing what others take away from them.

The Chetco Bar Fire in southwest Oregon started July 12, 2017 and burned over 191,000 acres.

Chetco Bar Fire map
Map showing the location of the Chetco Bar Fire (on the left) in southwest Oregon, October 2, 2017. USFS.