After mentioning that the roads are snowy and treacherous, someone might add the phrase verbum sap, meaning that they don't need to go on to tell you to drive extra slowly and carefully, or to stay home till the snow melts: You'll figure that out without having to be told.
Verbum sap is Latin, short for verbum sapientī sat(is est), meaning "A word is enough for the wise." Verbum means "word," and is related to the English words verb and verbal. Maybe you've heard the saying "A word to the wise is sufficient," which is the standard English version of verbum sap. People might omit the "is sufficient" part at the end, just saying "A word to the wise," because, well, a wise person doesn't need those extra words to understand what is meant.