Red Onion Harvesting

I get the directions on planting and the germination period and all that, but I was wondering something about the harvesting itself. Once the onion is ready to be harvested, what will it look like to let me know for certain that it is ready? Will the red onion bulb be seated above the ground, or will I have to "dig it out" from underneath the soil like all other bulbs?

I've been finding answers to many questions for the red onions, but they were pretty much all answering the same topics and none were answering "this" one. hehehe Thanks for any ideas that you might have regarding this particular issue!

By Charles