30 September 2007
Some news items not linked to over there: The Age, ABC Online, Sydney Morning Herald
Note: We are not calling for the use of additional fire danger categories by fire agencies, although we did include such in the report to focus on the upper reaches of fire danger.
A pretty sparse news report from ABC News indicating that roads in the Katherine region in the Top End of NT are closed due to bushfires. The Katherine fires are visible in the center of the images. There are several largish individual bushfires which encompass the general area. These individual areas are on the order of 50-100 thousand hectares each. Looking closely at the NAFI image indicates that some of the areas between the individual fire were burnt a few months ago (prescribed burning?), suggesting that these area may not join up into an even larger fire. Few fire scars are noted at this time in the 721 image.
To the east, in south-east Arnhem Land, a large area of active bushfire is seen. It encompasses about 1.2 million ha.
Down at the NT-Q:D border, the area of fire reported previously at Australia Bushfire Monitor, continue to expand and encompass new areas. The largest fire on the NT side
('Robinson River' on ABM) has burnt about 1.3 million ha. On the QLD side of the border, the fires have continued to expand towards the northwest. They have now burnt about 1 million hectares. A news report from the ABC discussed these fires a few days ago. A partoicularly prominent fire scar is seen on the NT side of the border.
Several new regions of relatively to the west of these fires. The largest is near Tanumbirin. It has a 'ring' of hotspots surrounding a prominent fire scar in the MODIS image. It has encompassed about 230 000 ha to date. An even more recent area of hotspots is seen further to the west. These regions are likely to continue to burn more in the upcoming week or so.
Finally, the Tanami desert fires are still going. As seen on the 721 image (and the NAFI map). The affected area is huge. Roughly speaking, this fire has impacted approximately 5 to 5.5 million hectares at this time
Fires in the remainder of the country will be discussed in the regular national update, due in a few days. The 10-day period ended on the 28th, but it seems to take them a few days to get the new composite up on the website, especially when a weekend is involved...(*_*)
22 September 2007
Large portions of the NT have been alight during this period. Extensive areas of hotspots are seen: Arnhem Land (eastern Top End), the Gulf regions of NT and QLD and the Tanami desert fires are prominent on the map. These fires as viewed on 18 September by the Aqua satellite, are shown in this image from the NASA Earth Observatory Natural Hazards website. A recent news item from ABC Rural also noted the ongoing NT fires.
At this writing, all the separate Tanami desert fire have now merged into one area of about 4.2 million ha. The main thrust of the fire is now towards the north. A few regions into WA in loosely the same region are showing some recent hotspots as well.
In west Kimberley, the large regions of bushfires which had been last noted in this post is also beginning to wind down. What I previously called the Thangoo fire, which was earlier affecting highway traffic, has now extended far to the east, and still has active hotspots. This fire has now burnt roughly 800 000 ha. Many of the others further north are out.
A fairly large area burnt is also apparent in SE WA. Tracing back through recent MODIS browse imagery, these look to have first been detected on 13 September. These look to be mostly out now, but another active area of hotspots was noted in the general area today.
Northwestern Cape York has an area of active fire. Closer examination indicates that there are several moderate sized fires currently burning in the 'greater Weipa' area. These are fairly separate, and appear to have been burned earlier in the season (probably in a controlled or prescribed burn)
Widely scattered hotspots were apparent in SE QLD and NE NSW. Houses in the Brisbane suburbs have been threatened during this period, but the threat has subsided to some degree. These fires were relatively small, but significant in terms of potential economic impact.
Very sparse hotspots are noted in souther NSW and SW WA. A few other isolated hotspots are also apparent in other regions.
18 September 2007
About 10,000 hectares of grazing property in the southern Gulf region of far north Queensland has been scorched by a massive bushfire.
A number of small fires in a region known as Hell's Gate, near the Northern Territory border, have merged to form a large fire currently burning on several fronts, a Queensland Fire and Rescue spokeswoman said.
These fires were first noted at Australia Bushfire Monitor in their incipient stage back on 12 Sep in the post “NT/QLD border fires”. Comparing the NAFI image from the afternoon of the 18th (about 3pm, below) with the previous image, the fires have grown quite considerably, especially those on the QLD side of the border. The NAFI image shows two close, but distinct regions with fire scars and/or hotspots in QLD. The westernmost one, the fire being report is roughly 130 000 ha bunt. The eastern fire is on the order of 175 000 ha
While these fires are large and serious, the true 'monster' out there are the fires ongoing across the border in NT. These fires have undergone a massive flare-up today. This fire has also expanded considerably since the previous update and estimates from NAFI now suggest that nearly 500 000 ha has been affected.
A smaller region, about 75 000 ha, near Billengarrah, NT is also active at this time.
The 500-m resolution true color MODIS browse image from the 0425 UTC overpass of the Aqua satellite is shown below. A massive smoke plume is observed in association with the easternmost NT fire. A relatively small (by comparison) smoke plume is seen with the QLD fires.
Why the flare-up? I have to say that I am at a bit of a loss as to the answer to that question. Observations at nearby stations from this afternoon suggests light winds, on the order of 10-20 km/h. Temperatures in the upper-30s. Humidity was a bit low, near 10% in the afternoon, but it doesn't seem particularly unusual compared to previous days. These observations suggest a GFDI on the order of 5, in the moderate category, while FFDI (although it is not forest) of around 30, in the very high category. Still, why today and not, say, yesterday? Is the non-linear response to slightly lower RH that severe?
There were fire bans issued further east in the NT today, in the Alice Springs and Katherine districts.
17 September 2007
Since the last report of the flare-up of the bushfires in the Tanami Desert a few days ago the area affected by the fires has grown considerably. A NAFI map from the afternoon of the 16th is shown below. Comparing this chart to the previous one shows the expanded area quite effectively.
Most of the fires in the region have expanded considerably. The large fire nearest to Tennant Creek and the fire east of Lajamanu have joined their burnt areas together. Recent hotspot activity has been indicated on both of these fires. The fire near Tanami Downs has also grown. In all, approximately 2.5 million hectares of the Desert has burnt in the in the last week to 10 days or so.
The so-called 721 image from the MODIS onboard the Aqua satellite is shown below. Resolution is 1 km and the swath was taken at ~0440 UTC. The image below is an extract. The fires were right on the edge of the swath, so the browse image is distorted. The merged burnt areas/fire scars are readily visible. Some pyrocumulus are also apparent in the center of the scar around the eastern Lajamanu fire.
Weather conditions do not seem to have been particularly severe. Relative humidity have been running the the 20-40% range and temperatures have been about normal. Winds have been generally moderate, although there were some strong early morning winds in the area on the 14th and 15th. The normal conditions probably produce something like a 'very high' GFDI-based fire danger rating
AS these fires are remote, there may not much suppression going on with them.
These areas should be very apparent in the next 10-day composite.
13 September 2007
The Terra satellite directly overflew the area at approximately 0120 UTC today (13 September 2007). An abundance of new hotspots were detected, as indicated by the purple stars in the NAFI image shown below.
The 250-m resolution 'true color' MODIS image is also shown below. The area of the fires is quite impressive on the image. The fire located about 150 km west of Tennant Creek shows the flare-up on the E and SE side of the rather large burnt area. A thick plume of smoke is seen rising from the area. The fire further to the west also has many active hotspots and a long plume of smoke extending from the fire.
The bright white patches within both smoke plumes are pyrocumulus clouds, that is cumulus clouds driven by the heat of the fire.
Several of the other fires noted on the NAFI map are also visible in the MODIS image. None appear as spectacularly in the image at this time.
A fire weather warning was issued by the Bureau and a fire ban until 5am on the 14th was issued by Bushfires NT was issued earlier in the day for the Alice Springs district. Fire weather conditions were extreme, with temperatures in the mid-30s, relative humidity running at about 20-25% at the time of the fires, with sustained winds of roughly 20-25 kts, with higher gusts.
Note: Image quality of the MODIS image has been degraded to make a manageable size picture.
12 September 2007
Weather conditions are not particularly favourable for fast-moving fire. While afternoon temperatures are high and relative humidities low, the winds are generally light in the vicinity, keeping fire dangers relatively low
The accompanying MODIS imagery is shown below. These images were captures at 0420 UTC on 11 September from the Aqua satellite. The first image is the so-called true-color image with hotspots indicated in red, grabbed from the near real-time browse images. Pixel resolution is 250 m. The smoke plumes from the two fires in question are clearly visible in this image. The second image is the so-called 7-2-1 image at the same time.
From the MODIS FAQ:
7,2,1 (2,155 nm: 876 nm: 670 nm)
Water=Black or dark blue
Desert/Naturally bare soil=Sandy pink
Burn scar=Red to reddish-brown, depending on the nature of the pre-fire vegetation and the severity of the burn.
Distinguishing burn scars from naturally low vegetation or bare soil. Enhancing floods.
This image has a 500 m pixel resolution. The hotspots are also shown on this image.
The burn scars associated with these fires are readily visible on both images. On the 721 image, the most recent burn scars are a deep red. Older fire scars have a lighter red color. On the true color image, the burn scars are also readily apparent and appear quite dark, looking like burnt spots (which of course they are...)
As something of an aside, the white splotches are small cumulus clouds, associated with the leading edge of the sea breeze. The sea breeze and the QLD fire are interacting at the time of the satellite overpass. The cloud pattern seems distorted at this point, with a band perpendicular to the coast apparently originating at the point of the fire. I am curious to know if this is merely coincidence or if the fire is affecting the atmospheric flow. (Perhaps the island off shore is also playing a role?)
10 September 2007
Most significant fire activity currently remains in the northern reaches of the country over this period.
Over the Top End, activity remains at approximately the same level as the last composite. Fires are particularly prevalent in the northern portions of Arnhem Land. Subjectively, the fires in that region are seemingly a bit more continuous than seen previously.
South of the Gulf of Carpenteria in NT near the QLD border, fire activity has increased since the last update. A large fire encompassing ~156 000 ha (estimated from NAFI) is currently active south of Robinson River. Several other fires are burning in the McArthur river district, but none as large as this eastern most case.
Two fairly significant fires are burning in the Tiwi Islands to the north of Darwin. The fire to the south is quite large. NAFI suggests the size of this fire is about 96 000 ha.
AS noted most recently here, quite significant fire activity continues in the Kimberley. The Thangoo fire and those on the Dampier Peninsula are quite apparent on the composite. Significant tracts of land have burnt in this region since August.
A small area of fires is burning in the Pilbara. These fires are isolated and relatively small at this time.
Several large fires are also noted in the Tanami Desert region of central NT. The fires in the vicinity of Tennant Creek continue to burn. Approximately another 165 000 ha has burnt in the western fire of these two, and about an additional 90 000 ha to the Eastern one. (This is in addition to what was reported earlier...). Large fires are also noted south of Lajamanu in the west (2 fires ~200 000 ha and 70 000 ha), near Tanami Downs (~300 000 ha). Several smaller fires, probably not visible in the composite, are burning to the south of these. This will most likely grow over the next week or two to become large fires.
A few fires are also apparent in the northern portions of the Cape York Peninsul in QLD. These are relatively small and isolated at this time.
Widespread isolated fires are apparent in SE QLD and NE NSW. None of these appear to be particularly large at this time, and may be agricultural fires.
Over the remainder of the country, very isolated hotspots are detected.
05 September 2007
Meanwhile, the Department of Environment and Conservation (DEC) believes bushfires are burning through more of the region's vegetation each year which poses increasing threats to wildlife in the process.
Ed Hatherley from the DEC says as more vegetative matter is removed, the landscape is becoming overrun by cane grass, which is highly susceptible to further fires.
He says the fires destroy the habitats of many native fauna species which leaves them vulnerable to predatory cats and foxes.
Mr Hatherley says while there are increasing efforts to coordinate fire management between pastoralists and government authorities, the problem is getting worse.
"Each year they're getting larger and more intense and covering a bigger area because of that simplification of the landscape," he said.
"We're on a downward sliding scale if you like and it's certainly not sustainable."
The map below, taken from NAFI late on the evening of 5 September, shows the extent of the fires which have burned this season. The Dampier Peninsula has been especially hard hit, and the fire near Thangoo, noted in the news item above, has already burnt in excess of 300 000 ha (I estimated 331 500 ha from NAFI...).
Also below is a MODIS image, taken from the real time website. The image has 250 m pixel resolution and is taken out of the 'browse image' posted in near real time on the MODIS website. It was captured around 0215 UTC (1015 WA time...) on 5 September. The smoke plume from the Thangoo fire is massive. Also showing active smoke plumes in the image are the fire on the central Dampier Peninsula and further north, near the coast.
Fire activity at this time is still concentrated in northern Australia. Fires in the western Kimberley continue, in about the same amounts as discussed in the previous update. This includes the fires on the Dampier peninsula, as well as those in more northern parts of the region.
Fire activity in the Top End of NT is still widespread, and at about the same level of activity. During this period, the in central NT, near Tennant Creek discussed here are also readily visible.
Fire is the Pilbara are apparently greatly reduced in number.
Also during this time, an 'East Coast Low' formed off the coast of Queensland, bringing a massive amount of rain and floods to portions of SE QLD. (It is very rare for these to form in August at this latitude...the last occurrence was in the late 1800s...). This has effectively dampened many of the fires, at least temporarily. In the hardest hit regions, the fire season is effectively over. Much of the flooding was particularly strong near the coast. Further inland, the potential for fire still exists.
Around the rest of the country, fire activity remains very low at this time.