“they impaled them.” Although most English versions say “hanged” instead of “impaled,” this hanging was not like our Western idea of “hung by the neck” but was an act of impaling. We see this with Jesus, who the Bible says was “hung on a tree,” but he was actually nailed to it; thus impaled on it.
It was the general custom in the Old Testament that the person would be killed first, and then the dead body was impaled and hung up for public display. The Assyrians, who were a very cruel people, often impaled people on upright stakes while they were still alive, and the Romans modified the act of impaling such that it became the horrible torture of crucifixion. The translation “impaled” is used in the NRSV; Tanakh; and Schocken Bible. Rotherham’s Emphasized Bible actually says, “crucified” here, but that is a historic anachronism when compared to Roman crucifixion.
“fell.” An idiom for died. Also, this may refer to the way they were killed before they were impaled. If they were stoned, which would have been customary, then they fell down after they were stoned to death.
“at the beginning of barley harvest.” So this would be very near the Feast of Passover.