Tornadoes, floods, blizzards and other forms of natural disaster can affect the city. The calculated initiation of nuclear war by any current power is considered unlikely. Nevertheless, general war could occur through accident, miscalculation and irrational act, or the unplanned escalation of a limited war, as well as by a deliberate act. (See county-wide nuclear attack contingency plan.) Major accidents such as train wrecks, plane crashes, explosions or accidental releases of hazardous substances are possible occurrences within the city. Civil disturbances and other public disorders are considered unlikely, but could occur in the city. Outside assistance from adjacent and higher levels of government, the military and non-government organizations may be available under localized emergency conditions. However, during de-spread disasters affecting large areas of the state or nation, outside aid could be severely limited or unavailable for long periods of time. In either case, the immediate, lifesaving aid must come from the jurisdiction most affected.