What's "ended in a disaster" in Chinese? I think it's 以灾难结局, and that people will understand that.  However, is there a more authentic term or is this it?
More native way is 災難收場.

～收場：


喜劇收場
悲劇收場
混亂收場


Another way is 大災難結局, for some big ending in drama and film.

大～結局 ：


大團圓結局


In writing, it could be 災難結尾.

～結尾：


歡喜結尾


You might use other words like 災難收尾, 災難而終.