Or. Admin. R. 629-048-0220 - Forecast Procedures
(1) There
are several concepts and procedural steps involved in accomplishing the Smoke
Management Plan objectives, designed to maximize opportunities for
accomplishing burning while minimizing the likelihood of public health effects
or visibility impairment in Class I Areas. The following sections of this rule
attempt to explain some of these concepts.
(2) The basic underlying mechanism in smoke
management is the use of an understanding of atmospheric dynamics and
combustion processes, in concert with current weather forecasts, to ensure that
the bulk of emissions from prescribed burning are transported to areas of low
or no adverse effect by:
(a) In the case of
broadcast or large pile burning, generating heat rapidly so that the fuel is
quickly consumed and emissions rise sufficiently above ground level to either:
(A) Become diluted and dispersed in the
atmosphere via transport winds to areas of minimal impact; or
(B) Mix with the moisture in clouds and fall
back to earth as precipitation; or
(b) In the case of low-intensity underburning
or small piles under the forest canopy, managing the volume of material burned
per unit of time and paying careful attention to surface winds to keep total
emissions low and disperse the smoke to relatively unpopulated areas.
(3) For each day that prescribed
burning is planned on forestland with Level 1 regulation, a weather forecast is
prepared by meteorologists specializing in smoke management. By examining the
atmospheric conditions predicted for the burn day, such as vent heights, mixing
layers, wind speed and direction, as well as information about what level of
pollutants may already be present in a given area, the meteorologists determine
if and where conditions will be favorable to accomplish burning.
(4) In addition to the weather forecast,
specific information is required on the location of planned burns, and the
tonnage of fuel that is expected to be consumed in a burn. This information is
provided on a per unit basis at the time that burns are registered and planned
with the forester (see OAR 629-048-0300).
(5) With knowledge of the information
described above, and based on dispersion models that have been developed
through time and experience, forecasters are able to reasonably predict how
much smoke can be put into the atmosphere, and at what locations, without
likelihood of threat to air quality objectives. This information is then
converted into instructions to field administrators and burn bosses as to what
tonnages, in what weather zones and at what distances from SSRAs prescribed
burning may be permitted.
(6) The
forecast and instructions are made available to field administrators and any
interested parties by 3:15 p.m. each day, as necessary. Locally, planned burns
are compared against the forecast and instructions, as well as any local
prioritization of burns, to determine which burns, if any, will be permitted on
the following day. If there are any changes in the forecast for the day of the
burn, the Smoke Management forecast unit will make every effort to place a
message on an automatic answering phone by 8:00 a.m.
Notes
Statutory/Other Authority: ORS 477.013, 477.562, 526.016 & 526.041
Statutes/Other Implemented: 477.515, 477.562 & ORS 477.013
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