Why has typhoon a "double etymology"?

The word typhoon appears to have a “double etymology”.

(Photo by NOAA via Getty Images)

For the longest time, it was said to come from Ancien Greek Τυφῶν (Tuphōn, “Typhon, father of the winds”). 

But as 大风 (dàfēng) means “big wind” in Mandarin and typhoons occur in Asia an not in Europe, this etymology is the correct one. The word is virtually identical in most languages, such as Arabic طوفان (ṭūfān), Hindi तूफ़ान (tūfān), and Persian توفان (tufân).

Wikipedia says that the Greek word is “unrelated but has secondarily contaminated the word”.

Interestingly, some believe that the Biblical Deluge may have been caused by the impact of a Comet called Typhon, maybe 7,000 years ago. If this is true, and earthquakes, tsunamis and other large scale phenomenons killed and destroyed all over the world, maybe the “double etymology” is not a coincidence after all

Finally, a crater found about 1,500km from Madagascar is said by some to be the resting place of this comet. 

Everything is connected!