Jefferson County Smoke Management Program

The Jefferson County Smoke Management Program is a cooperative effort of Jefferson County Seed Growers and the Jefferson County Rural Fire Protection District, committed to a safe, controlled agricultural field burning season that insures public safety and minimizes, to the greatest degree possible, impacts of smoke on the communities of Central Oregon.

Definitions

Open Field Burning:  Any agricultural burning not conducted in an authorized burn barrel, excepting areas smaller than one acre and irrigation ditches.

Propane Flaming:  Tractor-drawn propane burner makes consecutive passes across a field, burning along its path.

Blacklining:  Preparatory burn, often conducted early in the day while conditions are cool and damp, around the borders of a field.  This is a practice recommended for certain problem fields with adjacent fire hazards.

Test Fire:  A preliminary burn, authorized to assess atmospheric dispersion capacity, and therefore, to determine if open field burning may be advisable during existing weather conditions.

PiBall:  (Pilot Balloon)  The meterological instrument used to determine upper level wind directions and speeds.  A helium-filled weather balloon is released, then tracked using an instrument called a theodolyte.  The readings taken from this instrument as it tracks the weather balloon, up to 10,000 ft, can be used to calculate the wind speeds, directions, and the presence of inversions in the upper levels.

Mixing Height:  The lowest height at which the potential temperature exceeds the potential temperature at the surface.  In practical terms, it is the approximate height to which a smoke plume will rise, assuming good ignition, dry fuels, and winds less than about 15 mph.

Ventilation Index:   height of the mixing layer  X  the transport wind speed  

                                                            100