08/17/2015 Idaho DEQ Smoke Forecast

Updated 1130 am MDT Monday, August 17, 2015

Valid through: Noon MDT Tuesday, August 18, 2015

Smoke Outlook

Air quality is currently ranging from Good to Unhealthy across all of Idaho with higher impacts across the Clearwater Basin Drainage, the Treasure Valley, and the Salmon area.  Air quality is forecast to remain in the Moderate to Unhealthy category for the 24hr standard across central Idaho and Unhealthy for Sensitive Groups across the Treasure Valley.  Impacts are from regional fires burning in Washington State, California, Oregon, and a multitude of local fires in the Clearwater drainage, Central Idaho Mountains, and the Owyhees.

Nez Perce Reservation:  24-hour monitor readings range from Moderate to Unhealthy.  Hourly readings are fluctuating from Moderate to Hazardous, depending on location and wind direction.  The Nez Perce Tribe will continue their Air Quality Advisory.  Please contact the Nez Perce Tribe for more information: airquality@nezperce.org.

An upper level low pressure system will move along the Continental Divide today which, coupled with a flat ridge over southern Idaho, will provide a consistent northwesterly wind direction both at the surface and aloft.  Surface winds will be from the northwest-west across Idaho with northeast-northwest winds within the Purcell Trench and west-southwest winds across the southeast and eastern parts of Idaho.  Surface wind speeds will range from 10-15 mph in southern Idaho and 2-8 mph in northern Idaho.  Mixing heights are expected to be range from 4,000-9,000 ft AGL this afternoon which should promote vertical mixing.  Expect similar weather patterns and wind regimes for Tuesday.

The strongest smoke impacts are occurring across the Clearwater drainages and southwest Idaho.  This will continue into the afternoon and especially this evening.  Expect to experience impacts from Boundary/Bonner County line south to the Idaho/Nevada and Idaho/Utah border.  The highest impacts are expected to be within the drainages into Camas and Weippe Prairies, as well as down to the Lewiston-Clarkston Valley.  In southern Idaho, impacts will be greatest-although less than the impacts across northern Idaho- within the Treasure Valley, from Boise, west into Oregon, and north to McCall and Garden Valley and east along the Arco Desert within the Snake River Plain and through the drainages into the Salmon and Challis regions.  Nocturnal drainage flow will contribute to greater impacts in all of Idaho tonight, especially near the drainages into the Snake River Plain off the Central Idaho Mountains.  Consistent smoke coverage is expected across all of Idaho except across the Southeast Highlands, Teton Valley, and Island Park area into this evening.

DEQ Air Quality Advisories:

Idaho DEQ has issued a Stage 1 Forecast and Caution for the following areas:

·                     Latah, Nez Perce, Lewis, Clearwater, Idaho Counties, river corridors and surrounding areas (off the Nez Perce Reservation) effective  through 10:00am PDT August 18, 2015, at which time it will be re-evaluated and either extended or lifted.

·                     Ada, Canyon, Gem, Owyhee, Payette, Valley, Adams and Washington Counties effective through 3:00pm MDT August 18, 2015, at which time it will be re-evaluated and either extended or lifted.

·                     Cassia, Gooding, Jerome, Lincoln, Minidoka, and Twin Falls Counties effective through noon MDT August 18, at which time it will be re-evaluated and either extended or lifted.

·                     Lemhi County effective through 12:00pm MDT August 18, 2015, at which time it will be re-evaluated and either extended or lifted.

View real time smoke monitoring at:  http://www.airnow.gov/index.cfm?action=topics.smoke_wildfires

View DEQ near-real time monitoring at: http://airquality.deq.idaho.gov/

Smoke forecasts are dependent on predicted fire growth and weather.  If conditions change unexpectedly, impacts could occur.  When visibility starts to go below 5 miles, sensitive groups should minimize outdoor activities.  Everyone else should minimize prolonged or physical activity outdoors.  Visit the Idaho Smoke Blog for more information at http://idsmoke.blogspot.com/

Your eyes are your best tools to determine if it’s safe to be outside.  Even if you smell smoke, the air quality may still be good. 

AQI Category	Visibility (miles)
Good	11+
Moderate	6-10
Unhealthy for Sensitive Groups	3-5
Unhealthy	1½  -2¾
Very Unhealthy	1-1¼
Hazardous	Less than 1

How to estimate air quality based on visibility for areas without an air quality monitor or airport visibility estimate:

a. Face away from the sun.

b. Determine the limit of your visible range by looking for targets at known distances (miles).

c. Visible range is when an object you can easily see in the distance disappears.

d. Use the visibility values above to determine the local wildfire smoke category.