The efficiency of fire interventions relies on knowing the speed and direction of fire spreading. The calculation has to be based on relevant data. We examined the input data used by existing fire models, verifying which data are available, who collects them and whether they are of sufficient quality. When preparing a fire spread simulation, we would use data about the location and time of ignition, digital elevation model, current meteorological data, the weather forecast, land use and forest fuels. The input data needs to be adequately prepared. We present the preparation of data for the OE Sežana, a high-risk fire zone.