Adam clearly pointed out reasons for the incredible reversal today more from a fundamental perspective. Sentiment is horrible from Mom and Pop and from institutions too. The UK is not imploding is another storyline that gave some support. You can read the post here.
When looking at the price action and apply tools to it, that too told a story that said "the market is not doing what we all thought it should do". In technical terms, the price action moved above bias defining levels and buyers turned to sellers (for pairs moving higher)< and sellers turned to buyers (for pairs moving lower). When that happens, disciplined traders listen to "the market" and it can snowball the other way.
In this video, I show what I mean by looking at the price action and the levels that were in play before, during and after the CPI.
It is incredible, but it makes sense from a fundamental and technical perspective. The price action does not lie, and the good news is the storyline remains intact.