Fuel Model Attributes

GR1 (101)


The primary carrier of fire is sparse grass. The grass in GR1 is generally short either naturally or by grazing. This model has the dry climate moisture of extinction and is a dynamic model. If shrubs exist on these sites they will have little effect on fire behavior. This fuel model is often used to describe area of development such as agriculture or other disturbed areas such as recently burned or treated areas.

Fuel Model Statistics

Live Herb0.30
Live Woody0.00
FM Typedynamic
SAV Dead 1-hr2200
SAV Live Herb2000
SAV Live Woody9999
Fuel Bed Depth (ft)0.40
Dead Fuel Extinction Moisture15%
Heat Content8000

Rate of Spread

A series of graphs look at GR1 rate of spread under average and more severe conditions with no cover, an open stand, and closed stand.


Flame Length

When it occurs in a forested setting the canopy is usually in the open condition. When GR1 does occur under tree canopy, the crown base heights would need to be ≤ 3 feet in order for crown fire initiation even in dry windy conditions.