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A current fire threats dashboard is provided to help understand how the fire threat may be developing. THE OUTPUTS ARE NOT A GUIDE TO WHEN TO EVACUATE. ARMAC is predicated on you evacuating well in advance of the arrival of a physical threat and that is why it focuses on enabling remote decision making off site.
The two pages - which for convenience should, when the link is clicked - pop up here as separate browser windows - ( Current Fire Threats, and Current Fires Comparisons) utilise available data from the local Bureau of Meteorology weather station, the Victoria Emergency feed to provide a summary of fire threats in the vicinity, the Forest Fire Management (VIC) list of burnt areas, and the DEA satellite listing of hot spots. These are listed in order of closeness, with the main emphasis being on bushfires.
Estimations of arrival of fire front and ember attack utilise rules of thumb provided by CSIRO – that “on average” a fire front rate of spread (ROS) is usually about 8% of the open windspeed (at 10 m), and that ember attack moves at about 3 times the ROS, ie at about 24% of the wind speed. Great care should be taken in using this page as the actual ROS will depend on multiple factors including fuel dryness, terrain, suppression, gusts, and spotting behaviour which are not included. That said, here is a simple explanation of how to use the page
Using the Current Fire Threats
NB
- Most of the panels in this dashboard are expandable - so you see the full panel by clicking on the v symbol
- The sliders are for selecting a particular value for an angle, watch zone radius etc, as shown on the expanded panel.
The Current Fire Threats Dashboard brings together several independent sources of fire-related information to help you understand what is happening around the site right now, and how relevant those signals may be. It helps answer: What fires are nearby? How far away are they, and in which direction? And if ever, when might they plausibly affect this site?
Set your site coordinates
These are set in the Fire Defence Site Coordinates panel on the page. You can click the down arrowhead ("V" symbol) to expand this to allow you to put in longitude and lattitude. You can get your coordinates from Google Maps or elswhere.
What to look at first
Begin by inspecting the Fire Selection Controls (Vic Emergency...) panel. Clicking on the panel will produce a list of fire incident reports from Vic Emergency) with the 'distance and location noted in order of distance from the defence (house) site. The calculator takes into account Bureau of Meteorology data on wind direction.
The Downwind / Exposure panel has a slider where you can input the angle from the wind bearing to the house that you would consider the house being 'downwind'. So if that is set at 40 deg and the house is say 30 deg from the wind direction that would show the house as downwind = 'yes'. If set to 20 deg, then it would show the house as downwind = 'no'.
Looking at Fire Summary (Operational) panel One additional important detail is the data from which the distance has been calculated. This calculator takes account of whether a burnt area has been logged for the fire, and if it is closer than the incident report it calculates the distance from the closest burnt area edge.
The incident location, and the burnt edge may be quite dated numbers, although the burnt edge will be the more recent of the two. But there is a final way of calculating the distance from the fire which is updated every 5 minutes. It is the report from the DEA (Digital Earth Australia) satellite which regularly sweeps over the area logging hot spots. Now whilst recent those can be nothing to do with the bushfire. They might be a barbecue or a contained house fire. But if there is a cluster of those hot spots and they are retained and close to the fire front, chances are they represent the advance of the fire. Under Fire Selection Controls there are two sliders - one for the maximum distance to be taken into account in the Vic Emergency Incidents, and the other the strictness of the detection threshold which the cluster of hot spots must meet in order to be shown.
Expanding the Fire Selection Controls' panel
- VicEmergency Thresholds adds additional inputs of Watch Zone Radius (how far out fires are to be considered), Maximum Relevant Radius (how far out relevant fires are to be listed), Non-bushfire Max Distance (how far out non-bushfire fires are to be included).
- DEA hotspots clustering adds Query Radius (how far out hotspots are to be considered), Time Window (how far back in time hotspot observations are to be retained), Cluster EPS (how big the area of hot spots can be to be considered a cluster), and MIN points (the minimum points to be considered a cluster).
The Current Fires Comparisons Dashboard shows the three types of indicators of the distance of a selected fire from the house side by side so that the user can make their own judgements of the situation. Geometry selection logic is not affected by this display.
Each of the indicators has its own limitations:
- Incidents are simply the point at which the fire was first reported;
- Burnt areas will only be logged sporadically and only for big fires;
- Hot Spots will only appear for fires big enough and appropriately positioned to be observed by satellite.
The system automatically selects what it picks out as the most credible geometry available: confirmed burnt-area boundaries where available, and clustered satellite hotspots, and finally incident points (where the fire was first reported) as a fallback. The results of this are shown in the Thread Model (Wind-driven) panel as a potential time for arrival of Embers and fire front. The ETA for embers and fire front is based on very over-simplified assumptions and life and death decisions must not be based on it. At best it is a ready reckoner to assist human judgement based on all the information. Anticipate all advice from official sources as to when to have left the premises and ensure that you are well away before the advice is officially handed down!
In short: How to read the dashboard
The dashboard works best when read top-down and in combination:
Start with selecting a fire by distance, direction, and geometry source. Check wind direction and downwind status. Set desired acceptable angle from wind bearing. Review supporting evidence in the Fire Comparisons Table. Make your own judgements about the match between the three columns and their implications. Adjust sliders only if you want to explore the wider context. By all means read the ETAs but do so with scepticism and caution.
No single number should be interpreted in isolation. The strength of the system lies in its use of multiple independent data sources, cross-checked and presented transparently.
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