The basic forecast in these events is that of rainfall (or snowfall) and strong winds but additional factors have to be kept in view. For landslides, the strength of the rock and any damage already occurred at ground have to be considered. For avalanches, any undue accumulation of snow at a place or in a form where it could eventually break and come down heavily has to be watched.
For forest fires, the extent of dryness of the forest wood and the accumulated dry material (leaves, twigs, grass) has to be taken into consideration because these could get ignited either by a lightning stroke or by other causes.