25 CFR 170.206 - How is an emergency/disaster defined?
(a) An emergency/disaster is damage to an IRR transportation facility that:
(1) Renders the facility impassable or unusable; and
(2) Is caused by either a natural disaster over a widespread area or catastrophic failure from an external cause.
(b) Some examples of natural disasters are: floods, droughts, earthquakes, tornadoes, landslides, avalanches, and severe storms.
(c) An example of a catastrophic failure is the collapse of a highway bridge after being struck by a barge, truck, or landslide.