Even if your class is an on-campus/face-to-face class, you can use CourseDen/D2L as an emergency backup in the event of a campus closure. This plan could include things like emailing your students or utilizing CourseDen/D2L in order to communicate, to share assignments, and to give class quizzes. With resources such as CourseDen at your fingertips, you can easily maintain an "emergency teaching and learning area" just for your class.
However, do consider the context of the situation: For example, in the cases of extreme weather, you may have online/hybrid students who are stranded, without power, and/or lacking in Internet access. Please be understanding and prepared to adjust assignments, deadlines, and schedules where needed.