What struck me as strange is there is a similar word in Persian tundra for thunder? Now, my guess is the pronunciation in European languages changes after the Great Vowel Shift. So is that just a coincidence between the European and Persian languages? It is rare that word people would let such an assumption stand if there weren't some good evidence, see Online Etymology Dictionary.
E
Who has neither fools nor beggars nor whores among his kindred, was born of a stroke of thunder. ~~Romanian Proverb