What does "BLSN" specifically indicate when reporting weather conditions?

"BLSN" specifically indicates "Blowing Snow." This term is used in aviation weather reporting to denote that snow is being lifted from the ground by wind, creating reduced visibility and potentially hazardous conditions for flight operations. It is crucial for pilots and air traffic controllers to be aware of blowing snow as it can significantly impact visibility and runway conditions, making safe takeoffs and landings more challenging.

The phenomenon involves snow that is already on the ground being blown around, differing from snowfall where precipitation is actively falling from the sky. Understanding this distinction helps aviation professionals prepare for and respond to changing weather conditions effectively.