SMOKE MANAGEMENT
FORECAST AND INSTRUCTIONS
SALEM FORESTRY
WEATHER CENTER
OREGON DEPARTMENT
OF FORESTRY
ISSUED: Thursday,
April 30, 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 trough will approach the coast on Friday but stall offshore causing SW flow aloft. There is
a slight chance of afternoon mountain showers and possibly a thunderstorm going
into evening, snow levels around 9000 feet.
Skies will be partly to mostly cloudy with
temperatures near normal south but well above across
the north. Mixing heights only become
fair in afternoon in the Coast Range but still good for the Cascades. Winds will be light SW-NW.
EXTENDED DISCUSSION
On
Saturday the trough moves south to reach offshore California. It will continue to draw moisture northward
for widely scattered showers and a possible thunderstorm, mainly in the
Cascades. Up to .10” of moisture is
possible except more in a thunderstorm. Otherwise,
warm conditions continue under partly to mostly cloudy skies. Mixing conditions will generally be good in
the afternoon with light ENE-ESE transport winds.
The trough continues near the California coast on Sunday and
Monday. Scattered showers and possible
thunderstorms will be over the south half of the region as .25” of
precipitation is possible each day. Snow
levels continue around 9000 feet and temperatures range from 10-20oF
above seasonal. Burning potential remains
good on both afternoons with light NE-E winds on Sunday becoming NW by Monday afternoon.
2. DISPERSION
FRIDAY
Zone 601, 602,
603 and 612 (North Coast Range):
MORNING
Mixing height below
1000 ft early rising to 1200 - 2200 ft.
Transport wind NW
to N at 4 - 8 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising to 2500 - 3500 ft.
Transport wind W
to NW at 5 - 9 mph.
Surface wind similar to morning.
EVENING
Mixing height
lowers below 1000 ft.
Transport wind
increases to NW to N at 10 - 16 mph.
Surface wind
increases to WNW to NNW at 6 - 10 mph.
Zone 605-611 and
639 (North Cascades):
MORNING
Mixing height below
1000 ft early rising to 2700 - 3700 ft.
Transport wind
SSE to SW at 6 - 10 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising above 5000 ft.
Transport wind
SSW to WSW at 5 - 9 mph.
Surface wind similar to morning.
EVENING
Mixing height
lowers below 1000 ft.
Transport wind
shifts to NW to N at 8 - 12 mph.
Surface wind
increases to NW to N at 5 - 9 mph.
Zone 615-620
(South Coast Range):
MORNING
Mixing height below
1000 ft early rising to 1000 - 1900 ft.
Transport wind NW
to N at 4 - 8 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising to 2000 - 3000 ft.
Transport wind W
to NW at 6 - 12 mph.
Surface wind
increases to W to NW at 5 - 9 mph.
EVENING
Mixing height
1000 - 2000 ft.
Transport wind
shifts to NNW to NNE and increases to 10 - 22 mph.
Surface wind
becomes light and variable and controlled by local terrain.
Zone 616-623
(South Cascades):
MORNING
Mixing height below
1000 ft early rising to 1600 - 2600 ft.
Transport wind
SSE to SW at 5 - 9 mph.
Surface wind
light and variable and controlled by local terrain.
AFTERNOON
Mixing height
rising to 2700 - 3700 ft.
Transport wind
shifts to W to NW at 6 - 10 mph.
Surface wind
increases to W to NW at 4 - 8 mph.
EVENING
Mixing height
1000 - 1900 ft.
Transport wind
shifts to NW to NNE at 5 - 9 mph.
Surface wind
increases to WNW to NNW at 4 - 8 mph.
OUTLOOK:
SATURDAY
Mixing height
below 1000 ft early rising to 1600 to 2600 ft by late morning rising to 3500 to
4500 ft during the afternoon. Transport
wind N to NE at 4 - 8 mph during the morning becoming ENE to ESE at 6 - 10 mph
during the afternoon. Surface wind light
and variable.
SUNDAY
Mixing height
below 1000 ft early rising to 1100 to 2100 ft by late morning rising to 3900 to
4900 ft during the afternoon. Transport
wind NE to E at 4 - 8 mph. Surface wind light and variable during the
morning becoming N to NE at 4 - 8 mph during the afternoon.
MONDAY
In the north
mixing height below 1000 ft early rising to 2500 to 3500 ft by late morning
rising to 3500 to 4500 ft during the afternoon.
In the south mixing height below 1000 ft early rising to 1500 to 2500 ft
by late morning rising to 3800 to 4800 ft during the afternoon. Transport wind SSE to SSW at 5 - 9 mph during
the morning becoming WNW to NNW at 6 - 10 mph during the afternoon. Surface wind light and variable during the
morning becoming W to NW at 5 - 9 mph during the afternoon.
3. BURNING
INSTRUCTIONS FOR ALL ZONES IN THE WESTERN OREGON AREA
- Valid for burning done Friday, May 1,
2026.
=================================================================
Coast Range
Zone 601 and 612
Units should be
1000 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs. Restrict units in or near corridors to 500
tons or less.
Zone 602 and 603
Units should be
400 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs. Limit burning in or near corridors. Higher tonnage is possible south of the
Siuslaw River in Zone 603. Call the
forecaster.
Zone 615 and 616
west of R8W
Units should be
900 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs.
Zone 616 east of
R9W
Units should be
600 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs.
Zone 618 and 619
Units should be
1200 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs.
Zone 620
Units should be
300 tons or less, spaced 12 miles apart, and 12 miles from downwind SSRAs. Higher tonnage is possible south of
T35S. Call the forecaster.
Cascades
Zone 605, 606,
607, 608, 639, 610, 616, 617, and 623
Use standard
guidance matrix - see section 5 below.
Ensure adequate distance from downwind SSRAs for smoke to
dissipate. From T18S through T22S in
Zone 608 units should be 1200 tons or less, spaced 3 miles apart.
Zone 611
Units should be
1500 tons or less, spaced 3 miles apart, and 5 miles from downwind SSRAs.
Zone 620
Units should be
300 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.
Zone 622
Units should be
600 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs. East of R2W, use standard guidance matrix -
see section 5 below.
Siskiyous
Units should be
1200 tons or less, spaced 8 miles apart, and 10 miles from downwind SSRAs.
==============================================================
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.