How can you answer questions like "Are certain kinds of storms responsible to drive certain type of disease related group (DRG) admits?"?

Answering questions like this would require using data and statistical analysis of the data. You would need to collect storm data for a given location and combine it with the hospital visits data for the period before and after the storm and simply plot the correlation between each storm and the type of admits in the hospital around the same period. The findings must be validated by performing the similar analysis on data from another time period or a geographical location with similar characteristics.