SMOKE MANAGEMENT FORECAST AND INSTRUCTIONS

SALEM FORESTRY WEATHER CENTER

OREGON DEPARTMENT OF FORESTRY

 

ISSUED: Tuesday, April 21, 2026       2:30 PM      Gary Votaw

 

1.  DISCUSSION AND FORECAST FOR NORTHEAST FORECAST AREA ZONES 637-646

 

SHORT-TERM DISCUSSION

 

A strong upper-level trough passes over the state tonight and Wednesday with upper flow becoming N by the afternoon.  Conditions will be windy while widespread precipitation typically totals 0.50” to 1.25”.  Snow levels persist near 5000 feet as surface temperatures are 15oF below seasonal.  Mixing conditions are very good though with strong W-NW winds.

                                          

EXTENDED DISCUSSION

 

Light showers linger on Thursday as a secondary trough brushes by the area, snow above 4500-5000 feet.  Otherwise, conditions are partly sunny and chilly.  Mixing becomes excellent with NW winds.

 

NW flow aloft brings mostly sunny skies but still below normal temperatures.  Burning potential is very good with light NW transport winds.

 

There is a chance of light showers on Saturday as another trough approaches from the north.  Skies will be partly sunny while still cooler than normal.  Mixing will be excellent with very light N-NE winds.

 

2.  DISPERSION

 

WEDNESDAY

 

Zone 640, 642, and 644 West of R35E:

Mixing height above 5000 ft throughout the day.  Mixing height lowers to 3000 - 4000 ft during the evening.

 

Transport wind WSW to WNW at 28 - 48 mph during the morning and afternoon.  Transport wind decreases to W to WNW at 22 - 38 mph during the evening.

 

Surface wind WSW to WNW at 10 - 18 mph throughout the day.

 

Zone 637, 643, 645, 646, and 644 East of R34E:

Mixing height 4000 to 5000 ft throughout the day.  Mixing height lowers to 1500 - 2500 ft during the evening.

 

Transport wind W to WNW at 33 - 53 mph during the morning.  Transport wind decreases to W to NW at 25 - 45 mph during the afternoon and decreases to W to NW at 15 - 29 mph during the evening.

 

Surface wind NW to NNW at 12 - 24 mph during the morning and afternoon.  Surface wind decreases to WSW to WNW at 8 - 14 mph during the evening.

 

OUTLOOK:

 

THURSDAY

In the west mixing height 2000 to 3000 ft during the morning rising above 5000 ft during the afternoon.  In the east mixing height below 1000 ft early rising to 3900 to 4900 ft by late morning rising above 5000 ft during the afternoon.  In the west transport wind WNW to NW at 16 - 26 mph.  In the east transport wind WNW to NNW at 10 - 18 mph.  In the west surface wind light and variable during the morning becoming WNW to NNW at 6 - 12 mph during the afternoon.  In the east surface wind WNW to NW at 10 - 18 mph.

 

FRIDAY

Mixing height below 1000 ft early rising to 4300 to 5000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind WNW to NNW at 8 - 14 mph.  Surface wind light and variable during the morning becoming NNW to NNE at 4 - 8 mph during the afternoon.

 

SATURDAY

Mixing height below 1000 ft early rising to 4300 to 5000 ft by late morning rising above 5000 ft during the afternoon.  Transport wind N to NE at 4 - 8 mph.  Surface wind N to NE at 4 - 8 mph.

 

3.  BURNING INSTRUCTIONS FOR NORTHEAST OREGON ZONES 637-646

    - Valid for burning done Wednesday, April 22, 2026.

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

 

Zone 640, 642, and 644 West of R35E:

Follow standard guidance matrix - see section 5 below - for burning units to the WSW through WNW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 10 miles to the WSW through WNW in or near drainages leading to SSRAs.  No additional restrictions necessary. 

 

Zone 637, 643, 645, 646, and 644 East of R34E:

Follow standard guidance matrix - see section 5 below - for burning units to the W through WNW of SSRAs.  For units that will smolder significantly through the night avoid burning within at least 15 miles to the W through NNW in or near drainages leading to SSRAs.  Care needed in selecting units as smoke will likely fumigate along the ground in wind prone areas. No additional restrictions necessary. 

 

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

4.  SPECIAL NOTE:

 

    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

 

    The smoke management forecaster is available at (503)-

    945-7401. Please call this number and not individual's

    numbers to discuss daily burning.  For large burns (over

    2000 tons) or burns extending over a considerable period,

    please request a special forecast.  Avoid calling

    between 1:30 to 2:45 p.m.

 

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

    Daily/neo.htm

 

    To subscribe to or unsubscribe from the email list for this

    product, please go to the link:

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

 

    Please ensure your units have been planned and accomplished by

    checking: http://oregon.gov/ODF/FIRE/SMP/dailysmoke.shtml

 

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

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

    ?id=a7e321dc8fc444b7a33fbc67bc673a3b

 

 

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.

 

  * 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.