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Terwilliger Fire

Unit Information

Willamette National Forest
U.S. Forest Service
Springfield, OR 97477

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Incident Contact

Terwilliger Fire Information
Phone: 541-719-8135
Hours: 7:00am to 9:00pm daily

Highlighted Activity

09/19/2018 Terwilliger Fire Update September 19, 2018
Northwest Incident Management Team 8, Incident Commander, Doug Johnson September 19, 2018 - 9:00 A.M. Special Announcements: This will be the last update from the Northwest Incident Management Team.
News - 09/19/2018

The Terwilliger Fire was reported on August 19, 2018, around 3:21pm located approximately approximately five miles southeast of Blue River, Oregon.

Oregon Department of Forestry, US Forest Service fire crews and local landowners responded to suppress the fast moving fire.

Following extended initial attack efforts, additional personnel and equipment were ordered. An incident management team was requested to help manage the growing fire.

The fire surrounds the Cougar Reservoir and numerous recreation sites and prompted the Willamette National Forest to implement the Terwilliger Area Closure for public safety.

The Terwilliger Fire remains within the boundaries of the McKenzie Ranger District, Willamette National Forest, including the Three Sisters Wilderness.

The fire is being managed as a full suppression fire.

Basic Information

Current as of
Incident TypeWildfire
CauseUnder Investigation
Date of OriginSunday August 19th, 2018 approx. 03:21 PM
Location5 Miles SE of Blue River
Incident CommanderDoug Johnson, Northwest Incident Management Team 8
Coordinates44.084 latitude, -122.238 longitude

Current Situation

Total Personnel267
Size11,082 Acres
Percent of Perimeter Contained80%
Estimated Containment DateWednesday October 31st, 2018 approx. 10:00 AM
Fuels Involved

Closed Timber Litter, hardwood litter, Timber (litter and understory)

The fuels in the fire area consist of timber with dead woody understory, which are the primary carriers of surface fire. Heavy downed woody fuels are very dry due to the extreme drought. Resistance to control is very high due to steep slopes, deep canyons, large snags, deep duff, and heavy downed woody fuels in many areas. Lichen in the trees are a primary source of tree torching when fuels are dry.

Significant Events

Minimal Backing



Fire is spreading through creeping and backing, with low flame lengths and consuming heavy fuels (minimal fire behavior). Torching not observed, but is possible as the moss/lichen component is drying out and is becoming an available fuel on some of the trees. Burning debris (heavy fuels (1000 and 10000 hour fuels)) is still able to roll/skid down hill and deliver embers over the line; fire activity on most divisions limited to heavy fuels, snags, and sheltered duff/ground fuels. Overall, fire behavior minimal due to higher humidities and cloud cover; fire activity may pick up to moderate levels if RH drops enough for fuels to dry out before the next system arrives.


Planned Actions

Hold and mop-up containment lines. Check the fire spread and support ground resources by utilizing available air resources. Monitor the fire spread into the Three Sisters Wilderness for any threats to values at risk. Initiate suppression repair in appropriate areas. Coordinate with service contractors performing road clearing operations. Backhaul unneeded equipment to supply.

Projected Incident Activity

12 hours:

On Tuesday night, fire behavior will be minimal with good humidity recovery, with scattered clouds in the sky; early inversions possible with cold night air. Fire weakened trees & snags will continue to be a potential for fire spread due to falling & rolling material as fuels dry out.

24 hours:

Wednesday will be similar to Tuesday, as the flat NW flow continues the cool but dry weather, with slightly below normal temps, and higher RH. Fire activity may increase slightly with the drying of fuels; rollout of heavy fuels is still a concern on steep slopes. ERC's will continue to be at about average for this time of year.

48 hours:

Thursday will see a change, with a developing SW flow, ahead of the next incoming low pressure system. Breezier conditions with low temps & higher RH as the system approaches. ERC's should continue to be at or near seasonal averages for this time of the year.

72 hours:

On Friday, the Low pressure system will approach the fire area, with possible showers, lower temps, & higher RH. ERC's should continue to be near seasonal average, trending down as fuel moistures in the larger fuels increases; fire behavior should minimal after the next system is over the fire area.

Anticipated after 72 hours:

Saturday should see the exiting of the low pressure system, with lowered temps and increased RH, bringing fire behavior back to minimal activity. Fire should continue to consume any interior islands until season ending event, and fire within the Three Sisters Wilderness will continue to move E/SE slowly, until a season ending event.


Block 48-

6 pieces of heavy equipment including an excavator and 2 Chippers with 11 personnel total are represented in the tracked vehicle column due to a lack of options in resource types. These resources are private.

IMT is preparing for transfer of command to the Southern Cascades Type 3 Team on Thursday, September 20, 2018 at 0700 hrs.

Current Weather

Weather Concerns

A northwesterly flow continues with drier and warm conditions across the area today. Skies were mostly sunny with breezy afternoon winds. High temperatures 57-61 degrees Ridgetops, and 63-68 degrees Valleys, with min RH values 50-55% Ridgetops, 40-45% Valleys. Winds near the fire were out of WNW at 4-7 mph with a few gusts up to 10 mph.


A northwesterly flow is forecast across the area again Wednesday with drying conditions, slightly below normal temperatures, and breezy afternoon winds. Thursday into Friday, a developing SW flow is forecast a head of the next incoming low pressure system. The weather system is forecast to move across the area Friday afternoon / evening into Saturday morning. Cooler temperatures with a good chance of rain showers are forecast by late on Friday into Saturday morning. Highs 58-68 Wednesday, 60-70 Thursday, 55-65 Friday. Daytime Min RH values ranging from 40-50% Wednesday, 35-45% Thursday, 45-55% Friday.