A typhoon-watch warning has been issued for their final pool game against Samoa in Fukuoka on Saturday night.
Typhoon Hagibis is developing off the south coast of Japan, and could bring heavy rain and high winds this weekend.
If the match is called off, the two sides would share the points, taking Ireland's quarter-final ambitions out of their hands.
Should Scotland beat Russia with a bonus point and follow that with victory over Japan, the Irish would miss the playoffs and a potential final-eight showdown with the All Blacks.