It once happened that the elders descended from Jerusalem to their cities and decreed a fast because windblast the size of an oven's mouth was seen [on grain] in Ashkelon. They further decreed a fast because wolves had devoured two children beyond the Jordan [River]. R' Yose says: [The fast was decreed] not because they had devoured [the children], but [merely] because they were seen [in the city during the day].

In these cases we cry out [even] on the Sabbath: if a city is surrounded by [hostile] gentiles or by a [flooding] river, or if a ship is storm tossed at sea. R' Yose says: [We may call upon the people to assemble] for assistance, but not for supplication. Shimon the Timnite says: Also concerning pestilence; but the Sages did not agree with him.