FEMA 453 Design Guidance for Shelters and Safe Rooms

DHS has identified two emergency levels: routine and catastrophic,
as shown in Figure 4-1. The types of emergencies
that occur on a daily basis, such as car accidents, road spills,
or house fires, are routine events. Catastrophic events, such as
tornadoes, terrorist attacks, or floods, tend to cover a larger
area, impact a greater number of citizens, cost more to recover
from, and occur less frequently. Emergencies are complicated
as the extent increases due to the additional layers of coordination
and communication that need to occur as the event crosses
jurisdictional boundaries and overburdens the resources at the
origin of the event.
Figure 4- Preparedness versus scale of event
soUrcE: dHs nationaL gEosPatiaL PrEParEdnEss nEEds assEssmEnt
EmErgEncy managEmEnt considErations
4-3