Storm Impacting the Northwest U.S.; Fire Weather Conditions in Southern California; Severe Weather in the South

A Pacific storm is bringing areas of low elevation rain, moderate to heavy mountain snow, and high winds to the Northwest. Strong Santa Ana winds and very dry conditions are producing elevated to critical fire weather conditions in southern California. Isolated strong to severe thunderstorms are possible through early Wednesday morning across parts of northeast Texas into western Tennessee. Read More >

Interactive Clearing Index Map

Clearing Indices

Graphical Clearing Index

Clearing Index by Air Shed

About the Clearing Index

Clicking on the map will generate a Clearing Index table for the next 7 days for that location

Mouse over the images below to see better detail, or click for full scale view

Next 7 days							Airshed Map	Basin Map

The Clearing Index is an Air Quality/Smoke Dispersal Index used to regulate open burning and as input for other air quality decisions throughout Utah. The Clearing Index is defined as the Mixing Depth (depth of the mixed layer in 100s of feet above ground level) multiplied by the Transport Wind (average wind in the mixed layer in knots). Clearing Index values below 500 are considered poor ventilation and open burning is restricted under these conditions. Any Clearing Index values above 1000 are considered excellent ventilation and are referred to as 1000+. Data for the Clearing Index on these web pages are derived from several operational atmospheric computer models. The data will be reviewed and may be edited by NWS meteorologists before dissemination.

An example calculation of the Clearing Index:
Mixed Layer Depth =	10000 feet
Transport Wind =	8 knots
Clearing index =	(10000/100 feet) X 8 knots = 800

Note: Clearing Index is 1000+ if measurable precipitation or cold front passage occurs.

Utah Smoke Management Program

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