Whenever I point my toes I get arch and toe cramps, and then I have to flex my feet to stop them. When I try to point again–same thing happens. Even when I am very warmed up and at the end of class it happens. I used to take ballet and cramping never happened, maybe I should start taking ballet again. I started taking ballet as a kid BECAUSE I had arch cramps.
Maybe you didnt do same pointing when doing ballet. And for how long did you do yoga?
Cramp can be unaligned body , lack of magnesium and dehydration. Maybe there is more but these i have experienced.
Could be dehydration for sure. I forget to drink water until I am terribly thirsty. Thx
This advice helped me when I was cramping too. Try not to point from your toes. Feel the point in your arch and ball of foot instead.
Missi,
I have done that. ANY kind of extension of my foot brings it on even if I don’t involve my toes.
oh. well, then you’re just screwed. Just kidding! 
If it’s not some sort of potassium/dehydration thing, since you did well with ballet I’d say check out some ballet forums, they otherwise seem to suggest some extra focused foot stretching.