Resolves as Yes if an official IDF spokesperson declares the IDF has entered the city of Rafah en masse in Gaza. Because of the ambiguity of "en masse" and the potential for edge cases, other examples of things that would be strong arguments for Yes:
3+ Major news outlets such as CNN, the BBC, Al Jazeera, or the Washington Post describing the current Rafah operation as an invasion, territory taken, occupation, or taking an area such as western Rafah "under Israeli control".
The map here showing reported Israeli clearing operations across 10% or more of Rafah: https://storymaps.arcgis.com/stories/2e746151991643e39e64780f0674f7dd
An overwhelming preponderance of other prediction markets with similar language resolving Yes. Not just markets describing strikes in Rafah, but its full-scale invasion and at least substantial clearance.
If Joe Biden considers his red line on a Rafah invasion to have been crossed, that will be enough for a Yes.
Surgical raids of limited scope will not count, only a large scale clearing operation. If resolution is very murky as the month ends, up to a week will be taken after market close to wait for clearer evidence. If Rafah is invaded in May, this market will resolve No.
"At least 450,000 Palestinians have fled Rafah, according to the UN's agency for Palestine refugees (UNRWA), as Israeli officials say they will press ahead with plans for a full-scale ground invasion of the city."
"Build-up of Israeli forces near Rafah: The Biden administration has assessed that Israel has amassed enough troops on the edge of Rafah to move forward with a full-scale incursion in the coming days, but senior US officials are currently unsure if it has made a final decision to carry out such a move in direct defiance of President Joe Biden, two senior administration officials told CNN."