A family of Microsoft word processing software products for creating web, email, and print documents.
To add to what Doug and Charles have said, in older versions of Word, this used to happen with manual page breaks as well. Recent versions of Word avoid the problem by also adding a paragraph mark, when you insert a manual page break.
Of course, with regards to page breaks, there is another option: you can use "Page break before" formatting as an alternative. This possibility does not exist for column breaks.