Air Stagnation Advisory

URGENT - WEATHER MESSAGE
National Weather Service Boise ID
258 AM MST Tue Dec 30 2025

IDZ012-014-016-028-033-ORZ061>064-302200-
/O.EXT.KBOI.AS.Y.0005.000000T0000Z-260103T1200Z/
Lower Treasure Valley-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 Corral, Malheur City, Hill City, Burns,
Dunnean, Buchanan, Baker, Caldwell, Blaine, Boise, Fruitvale,
Nyssa, Cambridge, Fairfield, New Princeton, Mesa, Crane, Twin
Falls, Venator, Council, Indian Valley, Selby, Glendale, Nampa,
Ontario, Goodrich, Diamond, and Soldier
258 AM MST Tue Dec 30 2025 /158 AM PST Tue Dec 30 2025/

...AIR STAGNATION ADVISORY NOW IN EFFECT UNTIL 5 AM MST /4 AM PST/
SATURDAY...

* 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/ Saturday.

* 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 Missoula MT
1123 AM PST Mon Dec 29 2025

IDZ005>008-012000-
/O.NEW.KMSO.AS.Y.0002.251229T2000Z-260101T2000Z/
Northern Clearwater Mountains-Southern Clearwater Mountains-
Orofino/Grangeville Region-Lower Hells Canyon/Salmon River Region-
1123 AM PST Mon Dec 29 2025

...AIR STAGNATION ADVISORY IN EFFECT UNTIL NOON PST THURSDAY...

* WHAT...Stagnation conditions will trap pollutants, leading to
  deteriorating air quality.

* WHERE...Lower Hells Canyon/Salmon River Region,
  Orofino/Grangeville Region, Southern Clearwater Mountains, and
  Northern Clearwater Mountains.

* WHEN...Until noon PST Thursday.

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

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.

According to state air quality agencies, prolonged period of
stagnant air can hold pollutants close to the ground where people
live and breathe. Check with your local burn agency for any current
restrictions in your area.

&&

$$