The most disastrous fires for 65 years or more devastated over three million hectares (30,000 km2) over the summer of 2002/2003 in the Australian Capital Territory, New South Wales and Victoria - as well as in every other state! This followed upon the worst drought for a century or so. Fires burnt across the whole or part of a number of significant karst areas including Wee Jasper, Cooleman Plains and Yarrangobilly.

It must be emphasised that these are gross areas - even in one local area some parts will be affected by intense fire and adjacent areas will not burn at all. Indeed, as I write this sitting on the verandah of Yarrangobilly Caves House on a chilly March morning (and it snowed the night before last!), I can look across the valley of Rules Creek and see both totally burnt and unburnt areas. In the badly affected areas there are some individual untouched trees. See also the ANDYSEZ in this issue for more on fires.

The main potential environmental damage was at Church Cave, the surrounds of which were burnt over during the evening flyout from this important maternity cave (for Miniopterus schreibersii). The effect on the bat colony is unclear. Observations since the fire indicate that the bats are emerging normally - although perhaps a little earlier and over a shorter period than usual. With the enormous area of forest affected by the fires (see map) the availability of insects for the bats through this coming autumn to build there fat reserves for winter may be problematic.

Careys Cave escaped the fire, along with the village and camping area, but some damage occurred from subsequent heavy rain early in February. Some valuables from the village were stored in the cave at the height of the crisis, attracting media interest - cheering Geoff Kell up somewhat.

Small spot-overs from a tricky back-burn ignited small patches on Punchbowl hill area without known adverse impact. These were quickly extinguished by direct ground attack in heavy terrain - plus some helicopter water bombing. Running hoses out across well-developed karst pinnacles is not fun!

These small caves near Canberra have been burnt over - no other information is available.

These small caves near Canberra have been burnt over - no other information is available.

The Blue Waterhole fire trail was used a back-burn line and, in general, all the area to its east and north was burnt, including Clarke and Wilkinson Gorges. The area, as viewed from Blue Waterholes looks rather depressing although the area has not yet been fully inspected. The caves and karst upstream from Blue Waterhole are unscathed and Coolamine Homestead is intact.

Fire-fighters and water bombing helicopters saved the historic Yarrangobilly Caves House and visitor facilities on January 13, along with Cotterills Cottage.

The karst was extensively burnt over, with varying effects: the fire was very hot above Jersey and Jillabenan Caves but little or no ash has been observed inside. What the medium to long-term effects might be cannot be estimated.

Certainly changes to the internal cave environment will occur until the vegetation returns to 'normal'.

Local identities suggest that the so-called Yarrangobilly Plateau had not burnt since 1909. Some back-burning took place around the show caves precinct in 1965.

Speleologists with long memories will recall that, while heavily timbered, much of the Plateau area of 30 years ago had a relatively open ground cover that had gradually thickened to the point of virtual impenetrability in places. Not any more.

Based on a brief, and unsuccessful helicopter-based inspection and the progress of a major back-burn along the Snowy Mountains Highway, I expected the damage to vegetation to be far greater than has occurred - although I have not walked the whole area yet.

Some limestone has been calcined where logs were against limestone outcrops but other places (e.g. Deep Creek) have not been so damaged. The valley of Wombat Creek running up from Coppermine Cave may have been the hottest part of the fire.

Bushfires in this part of the country are episodic - every few decades perhaps - but they have been happening for a long time - certainly long before humans arrived to have an effect on the fire regime.

In Victoria, it is certain that Indi, Limestone Creek and Mitta Mitta karsts on the Dartmouth River have been burnt over - but no assessment of impact can be made as yet.

Happily, the fires were stopped at Gelantipy, about 25 north of Buchan, and just a few kilometres north of the Murrindal Caves - so no damage to the Buchan karst area. I am told cavers went to great lengths to prepare "Homeleigh" - the Buchan Caver's House - for the coming inferno, which thankfully didn't occur.

The Quaternary limestone at Ravine south of Yarrangobilly has burnt. There may well be considerable calcining of the strange limestone formations here.

The fire giveth and the fire taketh away ...

Having now had the luxury of a walk down the length of the limestone along the Yarrangobilly River and a visit to the now blackberry-free Ravine, I can now add to the above comments.

The walk revealed much of interest as the removal of the vegetation allowed the inspection of a variety of limestone outcrops, springs, alluvial terraces and other topographic features.

On the down-side there is more direct damage to the limestone than I had earlier thought including spalling of limestone flakes 2-8 metres above ground level on cliffs previously footed with blackberries and other fine fuel.

The fire front running up the hillside between the Glory Hole Cave and Castle Cave was extremely hot and there has been great damage to vegetation and rock.

Although there has been rain at Yarrangobilly there is little evidence of soil movement but there is plenty of potential ... And the weeds!

The removal of the vegetation at Ravine has revealed an extensive suite of tufa terraces and rimstone pools. And little, if any, damage to the Quaternary limestone karst.