Was there ever a F6 tornado?
There is no such thing as an F6 tornado, even though Ted Fujita plotted out F6-level winds. The Fujita scale, as used for rating tornados, only goes up to F5. Even if a tornado had F6-level winds, near ground level, which is *very* unlikely, if not impossible, it would only be rated F5.
Is there an EF0?
Around 60-70% of tornadoes are designated EF1 or EF0, also known as “weak” tornadoes, but weak is a relative term for tornadoes, as even these can cause significant damage.