Event storming is a workshop-based method to quickly find out what is happening in the domain of a software program.
Compared to other methods it is extremely lightweight and intentionally requires no support by a computer.
The result is expressed in sticky notes on a wide wall.
The business process is "stormed out" as a series of  domain events which are denoted as orange stickies.
It was invented by Alberto Brandolini in the context of domain-driven design (DDD).
Event storming can be used as a means for business process modeling and requirements engineering.
The basic idea is to bring together software developers and domain experts and learn from each other.
To make this learning process easier, event storming is meant to be fun.
The name was chosen to show that the focus should be on the domain events and the method works similar to brainstorming or agile modeling's model storming.