One of the most significant planning failures was that there was no plan for the effects of a levee breach with the mass flooding that would result. After a typical hurricane hit the region, the plan would be for disaster relief forces to reach the city by overland routes. Since there was no New Orleans mass flooding and isolation by flooding plan, the plan that was pulled off the books was the hurricane relief plan. This plan failed because the relief personnel, most of whom were in trucks, could not get past nor through the areas that were under water. That there was no mass flooding relief plan to be executed was obvious by the lack of any heavy-lift helicopters such as Chinooks in relief forces that would have replaced the usual truck-born hurricane relief forces. A mass flooding with regional isolation plan would not have used land-based relief forces at all overland relief was impossible because of the barrier in place with the flooding.