Large wireless network infrastructures experience concurrent or overlapping service outages due to equipment and link failures. The frequency, duration, and impact of such episodes are of interest to users and network operators alike. Here, a research project which investigates through simulation the characteristics of concurrent network outages in large wireless network infrastructures is presented. The dependability attributes used to gain a perspective on this issue are network reliability, availability, maintainability and survivability. To assess these attributes in this setting, a new term, called an "Impact epoch", is introduced.