Where does "up" begin?

The lovely little buds of the zwanenburg bronze crocuses continue their metamorphoses into cheery yellow-and-brown flowers.  I am wondering how I define "up".  Is it when the flowers open?  They were open yesterday afternoon, but not so much that I could see their innards; just enough to make a hole at the top.  Does that count?  What do I define as the start of the crocus season this year?  Paying attention makes new questions arise.  

I am enjoying the start of the season, though... it's still mostly below zero and so I love these tough little beauties for cheering me up so early in the year.  Sure, we'll still have snow storms and sleet and ice and rain but the flowers think it's spring so I'm not going to worry if our salt supply can last another 3 storms.  I'm not going to panic if I don't know where my walk-on-ice boot accessories (yak-trax for those of you in the know) are.  Winter's grip is loosening and I only need to step out my front door to remind myself.