What else would you call it?

There was nothing so unusual about the rift we were studying when it occurred so as to suggest a cause for the...development of the thing. It was exactly the same as any of dozens of others, save perhaps that Mister Dickerson and I were attempting to conduct magic through it. Which was successful, by the way. But it can't be a matter of excessive exposure to fadeiation, unless Madame Baudin once spent significantly more of her time closing rifts before you or I arrived.