Heat Builds in the West; Extremely Critical Fire Weather in the Northwest

A heat wave over the Southwest will intensify this week, peaking and expanding into the Intermountain West and northern High Plains this weekend. Critical to extremely critical fire weather conditions are forecast from the Northwest and the northern Great Basin this weekend. Particularly Dangerous Situation Red Flag Warnings have been issued. Read More >

Dispersion Index Table

DISPERSION INDEX TABLE

Dispersion Index	Interpretation
>100	Very Good (but may indirectly indicate hazardous conditions.)
60-100	Good (typical burning values)
41-60	Fair to Good (climatological afternoon values for most inland forests.)
21-40	Fair (stagnation if accompanied by persistent low wind speeds.)
13-20	Poor to Fair (stagnation, if persistent; better than average for nighttime.)
7-12	Poor (stagnant, but near average at nighttime.)
1-6	Very Poor (climatological nighttime value for most locations.)