Well
Lookleft didn't say it was VMC into IMC. They commented that they didn't understand that type of accident, after it was referenced in the original post.
Having said that, the OP said that a helicopter appeared to be in cloud/mist, and the areticle states:
However, due to weather conditions, the rescue crew was unable to land, forcing police to enter the bushland on foot.
, and in a referenced tweet:
Police crew has just arrived via helicopter. Plan is to winch investigators into the gully to access the crash site. Fog has now cleared allowing for better visibility.
So it does appear that the weather conditions will feature in the investigation.