SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Monday, May 4, 2026       2:30 PM      Gary Votaw

 

1.  DISCUSSION AND FORECAST FOR THE WESTERN OREGON AREA FORECAST ZONES 601-623 and 639

 

SHORT-TERM DISCUSSION

 

An upper-level ridge just offshore is causing NE flow aloft but weak onshore winds at lower levels.  Areas of morning clouds on Tuesday morning will break and skies become sunny, temperatures around 10oF above seasonal.  Burning potential for the afternoon is fair in the Coast Range but good for the Cascades.  Transport winds will be very light in the in the Coast Range, favoring NW-N, a little stronger for the Cascades from NW-NNE.

 

EXTENDED DISCUSSION

 

The ridge weakens slightly on Wednesday but rebounds by Thursday.  Both days will be mostly sunny and very warm with little noticeable change, still about 10oF above normal.  Mixing will still range from fair to good in the afternoons with light W-NW winds.

 

A weak trough arrives on Friday.  Skies will be partly sunny and a little cooler but otherwise dry.  Mixing becomes good in afternoon with light W-NW winds.

 

2.  DISPERSION

 

TUESDAY

 

Zone 601, 602, 603 and 612 (North Coast Range):

 

MORNING

Mixing height below 1000 ft early rising to 1500 - 2500 ft.

Transport wind light and variable and controlled by local terrain.

Surface wind light and variable and controlled by local terrain.

 

AFTERNOON

Mixing height 2000 - 3000 ft.

Transport wind similar to morning.

Surface wind similar to morning.

 

EVENING

Mixing height 1000 - 1700 ft.

Transport wind similar to afternoon.

Surface wind similar to afternoon.

 

Zone 605-611 and 639 (North Cascades):

 

MORNING

Mixing height below 1000 ft early rising to 2600 - 3600 ft.

Transport wind NNE to ENE at 5 - 9 mph.

Surface wind light and variable and controlled by local terrain.

 

AFTERNOON

Mixing height rising above 5000 ft.

Transport wind NNW to NE at 4 - 8 mph.

Surface wind similar to morning.

 

EVENING

Mixing height 1400 - 2400 ft.

Transport wind becomes light and variable and controlled by local terrain.

Surface wind similar to afternoon.

 

Zone 615-620 (South Coast Range):

 

MORNING

Mixing height below 1000 ft early rising to 1500 - 2500 ft.

Transport wind light and variable and controlled by local terrain.

Surface wind light and variable and controlled by local terrain.

 

AFTERNOON

Mixing height 2500 - 3500 ft.

Transport wind increases to NW to N at 5 - 9 mph.

Surface wind increases to W to NW at 5 - 9 mph.

 

EVENING

Mixing height 1000 - 1700 ft.

Transport wind becomes light and variable and controlled by local terrain.

Surface wind becomes light and variable and controlled by local terrain.

 

Zone 616-623 (South Cascades):

 

MORNING

Mixing height 1000 – 2000 ft early rising to 1900 - 2900 ft.

Transport wind WNW to NNW at 4 - 8 mph.

Surface wind light and variable and controlled by local terrain.

 

AFTERNOON

Mixing height rising to 4400 - 5000 ft.

Transport wind WNW to NNW at 8 - 14 mph.

Surface wind increases to WNW to NNW at 4 - 8 mph.

 

EVENING

Mixing height 1500 - 2500 ft.

Transport wind NNW to NNE at 6 - 10 mph.

Surface wind similar to afternoon.

 

OUTLOOK:

 

WEDNESDAY

In the Coast Range mixing height below 1000 ft early rising to 1600 to 2600 ft by late morning rising to 2500 to 3500 ft during the afternoon.  In the Cascades mixing height below 1000 ft early rising to 3300 to 4300 ft by late morning rising above 5000 ft during the afternoon.  Transport wind light and variable during the morning becoming WSW to NW at 6 - 10 mph during the afternoon.  Surface wind light and variable.

 

THURSDAY

Mixing height below 1000 ft early rising to 2000 to 3000 ft by late morning rising to 3600 to 4600 ft during the afternoon.  Transport wind light and variable during the morning becoming W to NW at 6 - 10 mph during the afternoon.  Surface wind WSW to NW at 4 - 8 mph.

 

FRIDAY

Mixing height below 1000 ft early rising to 2000 to 3000 ft by late morning rising to 3700 to 4700 ft during the afternoon.  Transport wind light and variable during the morning becoming W to NW at 8 - 14 mph during the afternoon.  Surface wind light and variable during the morning becoming WSW to NW at 5 - 9 mph during the afternoon.

 

3.  BURNING INSTRUCTIONS FOR ALL ZONES IN THE WESTERN OREGON AREA

    - Valid for burning done Tuesday, May 5, 2026.

=================================================================

 

Coast Range

 

Zone 601 and 612

Units should be 600 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs.

 

Zone 602 and 603

Units should be 300 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs.

 

Zone 615, 618, and 619

Use standard guidance matrix. (See section 5 below.)  Avoid burning directly upwind of the North Bend/Coos Bay SSRA.

 

Zone 616 west of R8W

Units should be 1500 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.

 

Zone 616 east of R9W

Units should be 1000 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.  Restrict units to 500 tons or less south of T30S.

 

Zone 620

Units should be 300 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.  Higher tonnage is possible south of the Rogue River.  Call the forecaster.

 

 

Cascades

 

Zone 605 and 606

Units should be 1500 tons or less, spaced 3 miles apart, and 5 miles from downwind SSRAs.  Verify transport winds away from SSRA if burning within 10 miles of the SSRA.  Higher tonnage is possible south of T20S in Zone 606 - call the forecaster.

 

Zone 607, 608, 639, 610, 611, 616, 617, and 623

Use standard guidance matrix - see section 5 below.  Ensure adequate distance from downwind SSRAs for smoke to dissipate.  South of T30S in Zone 616 units should be 1000 tons or less, spaced 6 miles apart.

 

Zone 620 and 622

Units should be 750 tons or less, spaced 6 miles apart, and 8 miles from downwind SSRAs.  East of R2W in Zone 622, use standard guidance matrix - see section 5 below.

 

 

Siskiyous

 

Use standard guidance matrix - see section 5 below. Ensure adequate distance from downwind SSRAs for smoke to dissipate.

 

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4.  SPECIAL NOTES:

 

    The ODF forecast smoke zones differ from the NWS fire zones and

    are available at:

    https://www.oregon.gov/odf/fire/documents/smoke-forecast-zone-map.pdf

 

    Call the smoke management duty forecaster at (503) 945-7401 to

    discuss burning. Please do not call individual's numbers to

    discuss daily burning. If the forecaster is not available,

    leave a message and they will return your call as soon as possible.

    Avoid calling between 1:30 to 2:45 p.m.

 

    The forecast is available on the Internet at:

    http://www.odf.state.or.us/DIVISIONS/protection/fire_protection/

    Daily/smi.htm

 

    Please ensure your units have been planned and accomplished by

    checking: http://www.oregon.gov/ODF/Fire/Pages/Burn.aspx

 

    A map of planned and/or accomplished burns is located at:

    http://geo.maps.arcgis.com/apps/webappviewer/index.html

    ?id=a7e321dc8fc444b7a33fbc67bc673a3b

 

    The forecast/instruction telephone recording is: (503) 945-7400.

 

    To subscribe to or unsubscribe from the email list for this

    product, please go to the link:

    http://weather.smkmgt.com/mailman/listinfo/

 

 

5.  STANDARD GUIDANCE MATRIX:

 

  * Greater than 5000 ft mixing height: Limit to 150 tons per mile

    from downwind SSRAs. Example: 75 tons allowed if burned a half

    mile from a downwind SSRA.

 

  * 3000 - 5000 ft mixing height: Limit to 50 tons per mile if burning

    within 5 miles of downwind SSRAs. Limit to 100 tons per mile if

    burning 5 miles or beyond downwind SSRAs.

    Example #1: 200 tons allowed if burned 4 miles from a downwind SSRA.

    Example #2: 500 tons allowed if burned 5 miles from a downwind SSRA.

 

  * Less than 3000 ft mixing height: No burning within 5 miles of

    downwind SSRAs. Limit to 60 tons per mile from downwind SSRAs.

    Example: 300 tons allowed if burned 5 miles from a downwind SSRA.

 

  * Ensure adequate spacing between units when burning near downwind

    SSRAs.

 

  * Use of polyethylene (PE) sheeting on greater than 75 percent of

    piles in a unit with 60 percent coverage per pile will allow a

    50 percent increase in tonnage over the existing instruction tonnage

    for that zone.

 

  * All exceptions must be coordinated with the duty forecaster

    prior to ignition.

 

 

6.  BURN MONITORING:

 

    Burns over 2000 tons must be monitored (OAR 629-048-0230(3) -

    7/1/14). Monitoring of all burns is highly recommended for both

    smoke management purposes and wildfire potential.