It built bit by bit and layer by layer. It was ignored by most as it showed no sign of moving. Gravity, though, cannot be defied forever.
The hacking scandal became a political avalanche which has swept aside the News Corps bid for BSkyB as well as the News of the World. It is now heading fast for the secretive network of relationships between newspaper proprietors, leading politicians and the police.
The Commons is echoing tonight to the sound of self congratulation. MPs believe that they have defied their media tormentors and won.
A few - like Labour MPs Tom Watson and Chris Bryant and the Business Secretary, Liberal Democrat Vince Cable - can say "we told you so".
The Labour leader Ed Miliband can't say that but today is a significant victory for him. His proposal for a Commons motion opposing the BSkyB takeover forced the government's hand. He has been rewarded for taking the brave step of confronting the Murdoch Empire before it was clear that it was in retreat.
The prime minister in the meantime has survived a major scare. Until today's announcement of a wide-ranging judge-led inquiry he has looked under the spell of events rather than in control of them.
Questions about his appointment of Andy Coulson and his relationships with the Murdochs and their lieutenants may yet cause him real damage.
This avalanche is still moving. No-one knows who or what lies in its path now.