Haines Index, also known as Lower Atmosphere Severity Index, is a weather index developed by meteorologist Donald Haines in 1988 that measures the potential for dry, unstable air to contribute to the development of large or erratic wildland fires.
The index is derived from the stability (temperature difference between different levels of the atmosphere) and moisture content (dew point depression) of the lower atmosphere.
A Haines Index of 6 means a high potential for an existing fire to become large or exhibit erratic fire behavior, 5 means medium potential, 4 means low potential, and anything less than 4 means very low potential.
From noon to 8 p.m. Sunday, a Haines Index of 5 or 6 is predicted, with wet to southwesat winds of five to 10 miles per hour, relative humidities of 10 to 20 percent and temperatures in the 80s in the mountains and low to mid-90s in the valleys.