The Blue Mountains City Council is currently dealing with the results of 101 such rock falls. At the moment, landslips have closed many major roads, such as the Mt Wilson Road, Jenolan Caves Road, and Wolgan Gap. The Great Western Highway is closed at Victoria Pass and Bells Line of Road is still under reconstruction. Repairs on some roads have been interrupted by further rockfalls, usually after heavy rains.
It’s my contention that it’s no coincidence that such rock falls are happening all at once. My research shows that nearly all the heaviest rainfall events (200ml or more) in the Blue Mountains have happened in the last few decades. Landslides are most likely to occur after heavy or prolonged rainfall, so they are likely to become more frequent as the frequency of rain storms increases, due to climate change. They are most likely to occur on talus slopes, which are frequently crossed by bushwalking tracks. Many bushwalking tracks have had to be closed because of landslides or rock falls.
I also contend that the size of such events is likely to increase. The Carne Wall collapse is an example – at 200,000 sq m, it was double the size of the famous 1931 cliff collapse at Katoomba (which was caused by coal mining). A visit to the newly re-opened Pulpit Rock lookout gives a good view of the Carne Wall rock fall and also many others in the same valley, all of which have happened in the last few years.
The NPWS is now closing some tracks when heavy rain is predicted, but it wasn’t enough to save the Singaporean/British family who died from a rock fall four years ago, Bodies of father and son killed in Blue Mountains landslide recovered by helicopter – ABC News
5 April 2022. British-born Mehraab Nazir, 49, and his nine-year-old son were killed when a shelf of rock fell on his family while walking on the Wentworth Pass track near Wentworth Falls. His 14 year-old son and 50 year-old wife suffered serious head and abdominal injuries. His 15 year-old daughter survived unharmed and was able to call for help. The family later took the NPWS to court over this incident (Nazir was a lawyer). There is no final ruling or verdict on damages yet, as the civil lawsuit against the State of New South Wales (NSW) remains ongoing before the NSW Supreme Court.
The family’s statement of claim argues that the National Parks and Wildlife Service (NPWS) failed to take reasonable precautions. They point out that the nearby town of Katoomba had recorded over 658mm of rain in the month prior—its highest average since 1894—and that a separate rockfall had occurred on the track just five days before the tragedy. The lawsuit alleges the track should have been closed to the public. Indeed, the track was closed on the days before and after the tragedy and the day that the family was on that track was the only day it was open that week.