National Weather Service United States Department of Commerce

The National Weather Service Offices in Aberdeen, Sioux Falls, and Rapid City will begin using the Grassland Fire Danger Index (GFDI) for the Grassland Fire Danger Statement and Grassland Fire Danger map in 2011.  The NWS in Aberdeen will resume issuance of all fire weather products on Monday, March 21, 2011.  The Grassland Statement itself will not change.


The GFDI output is based on a mathematical formula that uses temperature, relative humidity, wind speed, and curing data.  Curing is related to the “greenness” of the plant material.  Grass is a light-weight fuel that reacts quickly to changing weather conditions, which have a large and immediate effect on fire potential.  The GFDI also better represents the role of wind speed.  Recent studies have shown that wind often has the greatest effect on the overall fire danger for grasslands.


The Grassland Fire Danger Statements and South Dakota Grassland Fire Danger map are issued once a day during the fire season around 5 AM local time.  The Grassland Fire Danger values use the following categories, which correspond to the likelihood that grass fires will get out of control:


·         Low Fire Danger

·         Moderate Fire Danger

·         High Fire Danger

·         Very High Fire Danger

·         Extreme Fire Danger


The grassland fire danger forecasts can be used by emergency managers and fire officials for decision-making on issuing burn permits or burn bans. It may also be used for planning prescribed burns.


Links to South Dakota Grassland Fire Danger Text Products and Statewide Map: