Confirmed tornadic weather was in the area. You can never predict the weather or its effects. The storm came in Sat. afternoon. So those games had to be cancelled. Also, the tornado watch was still in effect at 8am Sun. morning. You have to err on the side of safety. You have to consider if there were down power lines, trees, etc. anywhere in the area. You could really create a more severe problem by getting all the hundreds of fans/players out there, and someone is injured by falling limbs, hot power lines, etc.
Safety is always best policy, and CUFC used best judgement possible-

http://www.wltx.com/news/story.aspx?storyid=59706