Given the tanker, probably a wild fire Edit: yeah, a big fire https://www.theage.com.au/national/victoria/victoria-fires-live-updates-emergency-warning-near-beaufort-as-mercury-soars-20240222-p5f6z6.html

Big bushfire

BMBR*** is the callsign Australia (and others?) use(s) for LAT/VLAT fire aircraft. The US uses TNKR***.

Bushfire, multiple aircraft attended the scene including a sky crane and a boing 737 outfitted as a waterbomber.