What would long and short term effects be from exposure to radiation fallout?

Very different: Very high ( > 100 rads), short-term doses of radiation have been known to cause early effects, such as diarrhea, skin burns, cataracts, and even death. It is suspected that radiation exposure may be linked to the potential for genetic effects in children of exposed parents. Longer term, lower level exposure is known to cause many kinds of cancer, and also cataracts.