the balloon goes up(redirected from balloon has gone up)
the balloon goes up
The situation becomes serious, critical, chaotic, or troublesome. Often used in the past tense ("the balloon went up"). If we don't get that shipment by Friday, the balloon goes up, and we lose the account. He tweeted it, and the balloon went up.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
balloon goes up, the
The undertaking begins, as in He's going to announce his candidacy for mayor-the balloon goes up on Monday. This expression comes from World War I, when British artillery sent up a balloon to notify gunners to open fire, this visual signal being more reliable than courier or telephone. It was soon transferred to signal other kinds of beginning. 
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
the balloon goes upmainly BRITISH
If the balloon goes up, something happens that causes a situation suddenly to become very serious. On the Saturday the balloon went up. Henry said he would be going out and not returning until the Sunday afternoon. Sara told him to take all his things and not to return at all. On the line was his solicitor warning that the balloon was about to go up. Note: In the First World War, balloons were used both to protect targets from air attacks, and to observe the enemy. The fact that a balloon had gone up therefore indicated that trouble was coming.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012