[Disambiguator]

We use a modified "F" scale for dust devils here in New Mexico.

The "F" rating is determined by the number of blue Wal-mart bags swirling around in the vortex.

[GSlob]

"The "F" rating is determined by the number of blue Wal-mart bags swirling around in the vortex."
The F rating is determined from the length and complexity of audible expletive pronouncements by those on the scene at the time.