Etiquette and techniques for rappelling past ascending parties

I'm going on a trip to red rocks canyon soon, and doing a few routes that are popular, which seems to suggest there may be other groups on the same route, something I don't have much experience with, particularly one route where the descent is rappels on the same belay anchors.

There seem to be a million different articles telling newbies how to rig a rappel, but none that cover what to do if your third rappel puts you onto the same pitch as another group of climbers. Is there a standard etiquette for communicating with groups above/below to coordinate throwing ropes? How should anchors be managed if a descending party and ascending party pass one another?

Saddlebags help.

When we climbed Crimson Chrysalis, ascending parties were aware and expecting other parties to be rapping. We were pleasantly surprised that in almost all cases they had rigged their belays to leave some space for us (generally means leaving some space on the right side for those raps). There was that one guy that had clustered his anchor on 3 bolts and used the rings... and insisted I anchor on the left bolt (rap swings in from the far right) which forced me to pull my ropes across him.  It was a cluster but we managed. I think he was already having a rough day, we did our best not to contribute to it. It would be nice if there was a separate rap line on that route in particular. 

communicate.  

FrankPS wrote:

Saddlebags help.

^ this. Saddlebag the rope so you're not dropping it on top of climbers below you. Or at the very least, clove hitch the rope ends to your harness when you toss the rope. Unless the rappel is very short, this will keep the rope from hitting the people below you. The first person down can rap with the rope ends clove hitched to their harness.

Mostly common sense. Ascending parties have the right of way. But typically folks will be more than happy to have you rappel through, since it gets you out of their way. Just ask them what works best for them as far as when to pull ropes, where to anchor, etc.

If someone's leading below you, wait till they are at a safe, comfortable spot before talking to them. Folks can understandably get a bit snippy when they're cruxing.

Don't throw the ropes. You may want to saddlebag anyway in land of the stuck ropes. If someone is leading, unless you can rap a good distance off their line, wait for their ok to go by. Same for pulling the rope. On your way up, you should be anchoring so that it's easy for another party to clip in to the bolts too. Never anchor through the bottom link of the chains or rap rings, leave those free for rapping. (something you should always do when using a bolted anchor that's also a rap station.)

Be friendly, communicate, and be patient. You may have to wait for leaders at every pitch. Leave yourself more time than you think you need for the descent. Then for your next climb, pick something with a walk-off. ;)

"Rope on ______ " ! ! ! ! ! !     <-- insert name of climb

I think the worst thing about ascending in two-way traffic is getting hit by ropes.  So by all means use saddlebags or some other way of flaking the rap line and carrying it down with you.  But it is when you pull your rope that the potentially worst situations happen, because when the rope releases from the rap anchor, you've got a full rope length starting to fall from above you that is going to go down a full rope length below you if the wall is steep and the ledges are small.  The section of rope at the end of the falling line is going to pack a wallop when it whips into someone a full pitch below.  So the most important thing, if the wall is steep with small ledges, is to check whether anyone is on the pitch below you.  Especially if someone is leading, do not pull your rappel until they are either up at your stance or on a part of the route that is protected from your falling rope.