Air Stagnation Advisory

URGENT - WEATHER MESSAGE
National Weather Service Boise ID
123 PM MST Wed Jan 21 2026

IDZ011>014-016-028-033-ORZ061>064-221400-
/O.CON.KBOI.AS.Y.0001.000000T0000Z-260123T1200Z/
West Central Mountains-Lower Treasure Valley-Boise Mountains-
Upper Treasure Valley-Western Magic Valley-Camas Prairie-Upper
Weiser River-Harney County-Baker County-Malheur County-Oregon
Lower Treasure Valley-
Including the cities of Cambridge, Burns, New Princeton, Council,
Baker, Anderson Dam, Goodrich, Buchanan, Crane, Diamond,
Glendale, Prairie, Mesa, Ola, Malheur City, Caldwell, Big Creek,
Fairfield, Fruitvale, Boise, Ontario, Cascade, Indian Valley,
Twin Falls, Blaine, Dunnean, Bear, Warm Lake, Hill City, Cuprum,
Nyssa, Corral, Soldier, McCall, Venator, Nampa, Selby, and Pine
123 PM MST Wed Jan 21 2026 /1223 PM PST Wed Jan 21 2026/

...AIR STAGNATION ADVISORY REMAINS IN EFFECT UNTIL 5 AM MST /4 AM
PST/ FRIDAY...

* WHAT...An extended period of stagnant air, with light winds and
  little vertical mixing. This is due to an inversion near the
  surface that will continue to trap pollutants.

* WHERE...Portions of south central and southwest Idaho and
  northeast and southeast Oregon.

* WHEN...Until 5 AM MST /4 AM PST/ Friday.

* IMPACTS...Poor air quality may cause issues for people with
  respiratory problems.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Persons with respiratory illness should follow their physicians
advice for dealing with high levels of air pollution during periods
of stagnant air.

&&

$$

LC

URGENT - WEATHER MESSAGE
National Weather Service Medford OR
1154 AM PST Wed Jan 21 2026

ORZ029>031-221200-
/O.CON.KMFR.AS.Y.0001.000000T0000Z-260124T0000Z/
Klamath Basin-Northern and Eastern Klamath County and Western
Lake County-Central and Eastern Lake County-
Including the following locations...Adel, Bly, Chemult,
Gilchrist, Klamath Falls, Valley Falls, Beatty, Olene, Paisley,
Fort Rock, Sprague River, Altamont, New Pine Creek, Crescent,
Midland, and Lakeview
1154 AM PST Wed Jan 21 2026

...AIR STAGNATION ADVISORY REMAINS IN EFFECT UNTIL 4 PM PST FRIDAY
WITHIN THE VALLEYS IN KLAMATH AND LAKE COUNTY...

* WHAT...Poor air quality will continue. This is due to an inversion
  and stagnant air conditions near the surface that will continue to
  trap pollutants Within the valleys in Klamath and Lake County.

* WHERE...The valleys of Klamath and Lake counties.

* WHEN...Until 4 PM PST Friday.

* IMPACTS...Poor air quality may cause issues for people with
  respiratory problems.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Persons with respiratory illness should follow their physicians
advice for dealing with high levels of air pollution during periods
of stagnant air.

&&

$$

BR-y

URGENT - WEATHER MESSAGE
National Weather Service Pocatello ID
931 AM MST Tue Jan 20 2026

IDZ054-059-221900-
/O.EXT.KPIH.AS.Y.0001.000000T0000Z-260122T1900Z/
Lower Snake River Plain-Franklin/Eastern Oneida Region-
Including the cities of Pocatello, Blackfoot, Shelley, Fort Hall,
Malad, Preston, American Falls, and Thatcher
931 AM MST Tue Jan 20 2026

...AIR STAGNATION ADVISORY NOW IN EFFECT UNTIL NOON MST THURSDAY...

* WHAT...Stagnant conditions will persist due to little vertical
  mixing and light winds. Degraded air quality is expected to
  continue as pollutants remained trapped near the surface.

* WHERE...Franklin/Eastern Oneida Region and Lower Snake River Plain.

* WHEN...Until noon MST Thursday.

* IMPACTS...Periods of air stagnation can lead to the buildup of
  pollutants near the surface.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If possible, reduce or eliminate activities that contribute to air
pollution, such as outdoor burning, and the use of residential wood
burning devices. Reduce vehicle trips and vehicle idling as much as
possible. Check with local agencies for possible restrictions in
your area.

&&

$$

Visit weather.gov/pocatello for more information.

McKaughan