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Smoke Update for Southwestern Oregon

Sunday July 28, 2019 9:00 am
The Fire:  
The Mile Post 97 Fire, located about 1 mile southeast of Canyonville was reported on Wednesday, July 24th at approximately 10:00 pm.  The fire is burning in timber, in steep, rocky terrain with limited access.   As of Sunday morning, the fire has burned 11,000 acres with 5% containment, and has spotted over to the east side of I-5.    Structures are threatened and level 2 “Get Set” evacuations are in progress for all residences on the west side of the freeway between mileposts 88-83.  The fire is being managed by the Oregon Department of Forestry is human caused.  There will be a community meeting at 7 pm tonight at Glendale High School.  

Weather: Currently, an upper level trough of low pressure is present in the Gulf of Alaska with a ridge of high pressure over southern California and Arizona.  This is creating zonal flow (westerlies) over southwestern Oregon at the upper levels.  At the surface, winds are from the north and light overnight, shifting to northerly to northwesterly with increasing speed during the day.  Nocturnal drainage flows are expected overnight under the evening temperature inversion.

Over the next 24 hours, the trough of low pressure in the Gulf of Alaska will start to dig south and the ridge of high pressure will push north into the Great Basin.  As a result, upper level winds over southwestern Oregon will begin to shift from westerly to southwesterly flow.   At the surface, winds will continue to be from the north, with shifts slightly towards to the southeast during the day and towards the southwest overnight.

Smoke (last 48 hours):

Grants Pass:  Smoke has been fluctuating diurnally with peak concentrations during the day time reaching 200 ug/m3 (very unhealthy) and clearing out overnight.

Medford/Ashland:  Highest concentrations of smoke have been overnight reaching very unhealthy levels overnight and moderate concentrations during the day.  

Klamath Falls: Smoke has been worse during the overnight hours, reaching the unhealthy levels occasionally.  During the day, smoke has been remained mostly in the moderate levels.  
Cave Junction:  Smoke has reached the unhealthy level during the day, with some improvement to the moderate level over night night. 

Coastal Communities (Brookings and Gold Beach).   No monitors are available so the following is based upon what is observed in the smoke models.  Even with the easterly push of smoke overnight, Brookings and Gold Beach appear to be clear of smoke.   However, just a bit south, Crescent City has experienced smoke. 

Smoke Forecast:   
Expect much of the same pattern to continue today with smoke pushing south of the fire during the day, and south-southwest during the late afternoon, shifting back to the south and southeast overnight.   Also some  lighter smoke is expected east of the fire affecting the communities of Tiller and Crater Lake National Park. This pattern is expected to continue for the next few days.  As such, the diurnal patterns of smoke we’ve seen the last few days are likely to continue. 

An Air Resource Advisor has been ordered and is expected to arrive on scene Monday morning.  This individual will be able to provide more detailed smoke forecasts and additional smoke monitoring once on scene.  

Disclaimer:  Smoke forecasts are subject to change as they are based upon forecasts of fire behavior and weather.  

Forecast prepared by Rick Graw, USDA Forest Service.