An outpouring is a gush, flow, or fast stream of something. An outpouring of lava from an active volcano would be a bad thing, but an outpouring of support from the community would be a very good thing.
A literal outpouring is something you can actually see, like an outpouring of water from a hose. It's actually more common to use outpouring figuratively, as in an outpouring of community support for a family of refugees or an outpouring of new work by a prolific artist. This noun dates from the fifteenth century, when it was first used to describe "a pouring out of spiritual things."