Portland, Oregon, is a city right next to northern west coast of the USA. Besides being very close to the sea, it is also laid on a river. The sun that heats up the ocean and the river leads to evaporation, causing water vapour to ascend, because of a few wind currents, this water vapour is taken to Portland's area where it colds down and condensates, raining over Portland.
Due, to know life on the moon there would be nothing to mess with the footprint, but the main reason why these footprints are going to last centuries is because "there is no weather." Since how there is no weather on the moon which means no wind there is no factors that could affect the footprint.
Hope this helps!
Yes, that's a true statement.
