I have confirmed that in my case, the delete trigger is happening before the update trigger, presumably because it is happening in alphabetic order as was stated earlier. But since the data being used by the update trigger comes from the 'new' object instead of from the current contents of the table, it does not matter that the underlying record may have already been deleted. (Of course, all triggers are fired within a single transaction, and inside a transaction, terms like "before", "after" and "already" are effectively meaningless. Right?)
RobR