In chapter 9 of Revelation we have the blowing of the last three of the seven trumpets. But these three trumpets, release what is called "woe." There are three woes, and each gets successively worse. As each woe is described it becomes clear we are not talking about something literal - indeed the descriptions are so strange it must be describing something highly symbolic and something of a spiritual nature. It would seem it is describing a demonic onslaught.