None can predict a disaster precisely: where, when, and how big a disaster will strike one area. This situation leads to uncertainty in such as required demand and supply availabilities. To an area that has been identified threatening by a natural hazard, a possible disaster scenario may compile. Since time is vital in disaster response operations, developing strategies to speed up emergency response is necessitated. This study is aimed to develop a stochastic model for a location-allocation problem in responding to a forecasted disaster. Our stochastic approach recommends a number and locations of local distribution centers (LDCs) that are required to be set up in the initial stage of the response phase and a number of relief items that will be dispatched to survivors in the affected areas through the proposed relief network. A mixed delivery strategy is applied in a 3-tier of a relief distribution network encompassing warehouses, LDCs, and shelters. This strategy provides the affected people in some of the shelters to receive relief items directly from nearby warehouses, while the remaining shelters will get supplies indirectly through the opened LDCs. Comparing to the indirect strategy that shelters are permitted to receive aid goods only through LDCs, the proposed mixed delivery strategy provides more efficient and effective relief distribution. The probable tsunami in West Sumatra, Indonesia, known as Mentawai Megathrust, is employed to illustrate the developed model. The model will be beneficial for disaster managers to improve the performance of a disaster relief operation.