1. A. PB-I and PB-II prescribed burns are allowed to be ignited only with a ventilation index category rated “good” or better, unless a waiver has been granted by the department. The ventilation index category may be obtained by contacting the department, or the burner may make the determination by calculating and documenting the ventilation index category using the following methodology:

   (1) using a computer with internet access, enter the national weather fire forecast website at http://www.srh.noaa.gov/abq/?n=forecasts-fireweather or successor universal resource locater (URL) internet address;

   (2) select the appropriate zone for the location of the burn project within the New Mexico map showing the various zones;

   (3) examine the forecast and find the reference elevation to be used to determine the general ventilation index category for the Bernalillo county zone (e.g., Albuquerque - 5,300 feet above mean sea level or Mountainair - 6,500 feet above mean sea level);

   (4) record the mixing height for “today” or “tomorrow” as appropriate;

   (5) calculate the mixing height at the burn location by adding the forecasted mixing height and the reference elevation obtained above. From the sum of these two items, subtract the elevation of the burn location; and

   (6) calculate the ventilation index for the prescribed burn by multiplying the mixing height at the burn location by the average forecasted transport wind speed.

2. B. Once the ventilation index for the prescribed burn has been calculated, refer to the following table to see if the ventilation index for the burn project is acceptable to ignite the burn:

   Category Knot-Feet Excellent - Acceptable Greater than or equal to 150,000 Very Good - Acceptable 100,000 - 149,999 Good - Acceptable 60,000 - 99,999 Fair - Not Acceptable 40,000 - 59,999 Poor - Not Acceptable Less than or equal to 40,000

   Category

   Knot-Feet

   Excellent - Acceptable

   Greater than or equal to 150,000

   Very Good - Acceptable

   100,000 - 149,999

   Good - Acceptable

   60,000 - 99,999

   Fair - Not Acceptable

   40,000 - 59,999

   Poor - Not Acceptable

   Less than or equal to 40,000

[20.11.21.17 NMAC - N, 12/31/03; A, 7/11/11]