On another note are there really radiation storms, if so then why? It's 200 years after the war for fucks sake,
Most likely Bethesda's people read about the radioactive twisters plaguing the mid west and thought to themselves "Hey we should have something like that too." However there are not much tornadoes on the East Coast so they went sort of 'space sci fi' and introduced radiation storms.
Problem is, they don't make sense.
You see Bethesda, the twisters themselves aren't radioactive, they are just extremely fast winds. Its the sand and debris they carry.
It is also why a sand storm can be radioactive.
Having storms of just random radioactivity makes no sense (well at least not here on Earth, anyone know of storms on other planets that have a fission 'effect'?)