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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 Personnel210
Size11,082 Acres
Percent of Perimeter Contained80%
Estimated Containment DateWednesday October 31st, 2018 approx. 10:00 AM
Fuels Involved

Primary Fuel Model, Materials, or Hazards Involved (hazardous chemicals, fuel types, infectious agents, radiation, etc):

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

The fuels in the fire area consist of timber with understory of dead woody fuels, 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 fine fuels are dry.

Significant Events

Observed Fire Behavior or Significant Events for the Time Period Reported (describe fire behavior using accepted terminology. For non-fire incidents, describe significant events related to the materials or other causal agents):






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 in the Three Sisters Wilderness for any threats to values at risk. Continue suppression repair in appropriate areas. Coordinate with service contractors performing road clearing operations. Backhaul unneeded equipment to supply.

Projected Incident Activity

12 hours:

On Wednesday 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:

Thursday will see a change begin in the pattern, with a developing SW flow, ahead of the next incoming low pressure system. Breezier conditions with slightly higher temps & RH in the 35%-40% range as the system approaches.. ERC's should continue to be at or near seasonal averages for this time of year.

48 hours:

On Friday, the Low pressure system will approach the fire area, with possible showers in the evening, 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 with the next system is over the fire area.

72 hours:

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

Anticipated after 72 hours:

Sunday will see continued chance of showers until midnight; fire behavior minimal with the low temps, and elevated RH. A slight chance for an East Wind event to occur, but may be more to the south of the fire area. Spot forecasts should be done to be aware if the event occurs. Fire behavior still likely minimal as fuels are burned out, and many areas are sheltered from an east wind event.


Block 48-

14 pieces of heavy equipment including 4 Excavators and 2 Chippers with 26 personnel total are represented in the tracked vehicle column due to a lack of options in resource types. These resources are private.

Transfer of Command to the Southern Cascades Type 3 Team will occur tomorrow, 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 58-64 degrees Ridgetops, and 65-70 degrees Valleys, with min RH values 40-45% Ridgetops, 35-40% 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 Thursday with drying conditions, slightly below normal temperatures, and breezy afternoon winds. Starting late Thursday evening into the weekend, 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 60-70 Thursday, 55-65 Friday. Daytime Min RH values ranging from 35-45% Thursday, 45-55% Friday.