Fire Danger Ratings: an embarrassment of riches, or just confusion?

You can see the Forest Fire Danger Rating for Friday 25 October on the right.  The whole of the Lockyer Valley Region is rated Low-Moderate.

The Grassland Fire Danger Rating for Friday is available by clicking on the Legend on the right, or by going to the Emergency Information - Queensland website.  You'll have to change a "layer" setting to display the FDR info on the map (click the Layer tab, then click the Real Time tab, and click on the toggle beside the Fire Danger Rating label).

Their Grassland Fire Danger Rating map looks like this:

A much nicer image than the one on the right which is from the Rural Fire Service Website (though it has no more FDR information in it), and you might notice that the area west of Toowoomba is yellow, which indicates a Very High Grassland Fire Danger Rating - rather than the High Forest Fire Danger Rating in the map to the right.  There are good reasons for the differences between Forest and Grassland ratings which I won't go into here, but so far I haven't found any good explanation of which one you should be looking at.  I guess that if your property (and most surrounding properties) is mostly grassland then the Grassland rating would be most relevant.

However there are plans to adopt the BOM fire danger rating system in Queensland.  We are one of only two areas in Australia which have not made the transition, the NT being the other one.

You can see the BOM fire danger rating here:  http://www.bom.gov.au/qld/forecasts/bushfire.shtml, and at the time of writing (10.22pm on Thursday night) it was High. But this was the fire danger rating for the whole of the Southeast Coast Region - the BOM doesn't give fine-grained fire danger ratings like the Rural Fire Service does.

If anyone can give me an explanation of when one should look at the Forest Fire Danger Rating rather than the Grassland Fire Danger Rating, and how these differ from the BOM Fire Danger Ratings I'd be grateful.  Feel free to use my smokespotter email: smokespotters [at] gmail [dot] com.