It varies widely. In some cases a tornado can be heard over a mile away, in other cases you can't hear it until it's just about on top of you.
Tornado sirens or alarms are designed so that they can be heard at least five miles away. Tornado sirens are placed in cities and towns and rural areas so that people can be warned well in advance of a tornado.
please use complete sentences and words... "for m a tornado" makes no sense
It is safest to stay underground if you hear/see a tornado.
From 10 meters away .
200 kHz
That depends on how far away the next destination is and how fast the tornado is traveling.
"Hear" They can HEAR something up to 5 miles away
a lynx can hear a prey from 65 metres away
almost instantly.
ultrasonic
25 miles away
2 miles