Storm Systems to Impact the Central and Eastern U.S. Through the Weekend

Two storm systems will track through the central and eastern U.S. today through this weekend with areas of gusty winds, rain and heavy snow. Severe thunderstorms and heavy to excessive rainfall is forecast today from the Lower Mississippi River Valley to the Tennessee Valley. Damaging winds, a few tornadoes, and areas of flooding are possible. 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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