Three Sisters Loop in August

You need a permit if you camp in the Obsidian area. There are signs on the PCT that say this on both sides. It's from 0.4 miles North of Glacier Way Trail junction to 0.2 miles South of Obsidian Trail junction just South of Obsidian Falls .

I ran into a ranger that told me this as I was walking through there. Somewhere I read that thru-hikers were exempt. Maybe that's for people hiking further than just around the mountain.

I've camped there several times without a permit and no one bothered me. Before I knew of the prohibition.

If you're going South, you could get water as you're just past Obsidian Falls, then walk another mile to some nice flat areas just outside the area.

If you're going North, get water at the Glacier Way stream. Then there's someplace to camp within a mile.

Or just camp discretely and deny any knowledge of camping prohibition : )

About the only other restrictions are you have to camp at sites marked with a post at Moraine Lake and Green Lakes.

I really like that trail between South and Middle Sisters and the area just South of Brokentop.

The portlandhikers.org field guide has more detail than anything else I've seen (seeing as I wrote it : )

Yes, I saw your write-up in the Field Guide, and I'm taking it for my inspiration. That's how I knew to call out to you (how many Jerry Adams could there be that are that active in the hiking community in Oregon?) The other write-up I've seen is in Backpacking Oregon, by Douglas Lorain. That's the one that enters via the Obsidian Trail.

I'm expecting pretty warm temperatures for mid-August, but recently hikers moving through on the PCT experienced cold rain and day-time temps around the 40's. Looking at the current conditions on the Deschutes National Forest page for the area, snow level is around 6500 feet, but I'm guessing that 3 weeks from now that will have changed dramatically. We got blown off the Obsidian Trail last September by that big storm the last week-end–converted from backpack to day hike, was the worst conditions we've ever hiked in–found it weirdly fun and exhilarating.

Any commentary on local weather?

My standard weather forecast tool is http://forecast.weather.gov/MapClick.php?lon=-121.81668&lat=44.12394

You can pan around and select the weather report for any spot, including somewhere along the PCT or wherever. Not totally accurate but good idea.

A couple years ago I was hiking along the PCT to the Obsidian area in late August/early September. It was snowing, windy. I camped in the Obsidian Area without a permit. There was no one else so I didn't worry about permit. You got to be prepared for bad weather at any time.

A lot of recent trip reports from around there. Snow is rapidly becoming a non issue. The term "snow level" becomes less meaningful now. If you happen to cross a slope that's protected from the sun it can still have snow, but it's warm, not icy, easy to just walk over. Not so much snow you can't figure out where the trail goes.