There are several instances that recur to the distinction between ordinary and extraordinary. For example wind. For instance:
Sukkah must withstand ordinary wind (Orach Chayim 630.10)
When one wind is considered ordinary and when extraordinary wind? There's a distinction, but not definition, in Bava Kama 45:
- The prevailing wind is: ru'ach Metzuyah.
- The unusual strong wind is ru'ach she'Eino Metzuyah.
Is there something that marks a difference between them? how to decide whether it is one or the other?
EDIT: Possible criteria to evaluate between prevailing and unusual wind were:
- Succah construction dictates unusual wind: local experience may have led to improve the construction of succah to resist the prevailing high winds. So, a wind that damaged the succah built according to the common practice was a unusual wind.
- The local elderly or writings dictates unusual wind: what the older people of the community remembered, or a written historical record, was an unusual wind.