What happened here?

For my birthday last weekend in Flagstaff, my mom and I decided to make a carrot cake. The same one that I've made several times recently, and always turns out great. We picked carrots from the garden, which were perfect.



And then, of course, did not exactly follow the recipe (my mom likes to substitute...), but look what happened!



All over the bottom of the stove. It actually still tasted really good though. So, was it (a) using olive oil and butter instead of canola oil, (b) using half whole wheat flour instead of just all-purpose flour, or (c) the altitude in Flagstaff?