A state of emergency is a situation in which a government is empowered to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. It is typically declared in response to an extraordinary situation posing a fundamental threat to the country, such as an armed action against the state, a natural disaster, civil unrest, an epidemic, a financial or economic crisis, or a general strike. The declaration may suspend certain normal functions of government, may alert citizens to alter their normal behavior, or may authorize government agencies to implement emergency preparedness plans as well as to limit or suspend civil liberties and human rights.

A state of emergency can be declared by the Governor of a state or province, or by local mayors or governors, depending on the jurisdiction. It allows the government to act more quickly than it can during non-emergency times, and enables it to make resources immediately available to rescue, evacuate, shelter, provide essential commodities (i.e., heating fuel, food, etc.), and quell disturbances in affected localities. It may also position the state or province to seek federal assistance when the scope of the event exceeds its resources.

During a state of emergency, citizens may receive instructions from state officials to take certain actions, such as evacuating or sheltering in place, depending on the nature of the emergency. Travel restrictions may be implemented if necessary, but a state of emergency does not automatically mean that a travel ban is in place. Schools, businesses, and government offices may or may not be closed, depending on the situation and the decisions made by state officials. The Governor or other authorized officials have the authority to exercise any and all authority over persons and property necessary to protect the public.