Sunday 12 February 2017
The fire weather forecast for Sunday was 'as bad as it gets'.
The fight continued early on Sunday. Throughout the morning, the fire spotted over containment lines in several locations but firefighters were able to stop the fire getting away.
That morning the wind increased dramatically and by around 10am more spotovers had occurred, including near the Golden Highway which was then closed. As the fire started spreading to the east, it was upgraded to Emergency Warning, the highest level of bush fire alert.
Telephone warnings were sent to properties in the immediate path of the fire. Throughout the day eight Emergency Alert telephone warnings were sent as the fire moved quickly and impacted on communities, including the areas of Uarbry, Turill, Cassilis, Merriwa, Coolah and Leadville.
The village of Uarbry was heavily impacted by the fire. Firefighters, aircraft and farmers worked hard to protect properties.
However under the hot, dry and windy conditions, there was little that could be done and many of the buildings in the village were destroyed.
As conditions continued to worsen, and with roads in the area becoming extremely dangerous, the focus turned to protecting life - including ensuring the safety of firefighters.
Throughout the day, the fire continued to spread and build in intensity.
Under the Catastrophic conditions, it was becoming too dangerous for firefighters remain in the path of the head of the fire and residents between the fire and Cassilis were told to relocate to the village of Cassilis.
Fire prediction maps showed that there was a very real risk to the village. Indeed, the worst case scenario was that Cassilis would be surrounded by fire, especially as the forecast southerly change moved through.
Fire prediction map from the afternoon of Sunday 12 February 2017. The red lines show the forecast perimeter of the fire at different times. In the centre of the map you can see Cassilis identified as a threatened community.
Strike teams were placed in the town to protect it and its residents, as well as the many people who heeded the warnings and relocated there.
Fortunately, the southerly change moved in early, before the fire should reach the township and its people.
Also, the backburn undertaken the previous night is thought to have stopped the fire breaching containment lines for about two hours. If it hadn't, it is possible that the fire would have reached Cassilis.
Fire conditions 'as bad as it gets'
Temperatures on the day were in the mid-40s and winds were hot and dry. Under a Catastrophic fire danger rating, these are the worst conditions possible for a fire.
Under these conditions, homes are not designed to survive a fire and the focus is on protecting life.
The Sir Ivan fire grew in intensity, producing so much smoke, that it produced a 'pyrocumulonimbus' cloud.
The fire started to create its own weather system, with a large cloud of smoke producing lightning.
These lightning strikes started new fires well ahead of the fire - some as many as 80 kilometres away from the firefront.
It is believed that the smoke cloud was close to 'collapsing', which would then create a violent storm with winds of around 100 kilometres an hour.