The Lower Atmosphere Stability Index, or Haines index, is computed from the forecast soundings from across the area.. The index is composed of a stability term and a moisture term. The stability term is derived from the temperature difference at two atmosphere levels. The moisture term is derived from the dew point depression at a single atmosphere level. This index has been shown to be correlated with large fire growth on initiating and existing fires where surface winds do not dominate fire behavior.

Haines Indexes range from 2 to 6 for indicating potential for large fire growth:

The Burning Category, is computed by multiplying the transport wind speed and the mixing height. This number is called the ventilation index. The ventilation index is then correlated to a table of burning category values. The lower the burning category (BC), the poorer the smoke dispersion. These Values are listed below.

Burning Category          Ventilation Index (KT-FT)
      1                         28,500 or less
      2                         28,500 to 38,000
      3                         38,001 to 51,000
      4                         51,001 to 95,000
      5                         Above 95,000

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