Here's an excerpt from the e-mail I sent out to my friends during the planning stage for this year's dive:
"Since this is not an organized event, I want to stress that this is done entirely at your own risk. We're just letting some folks know because they may have shown an interest in diving here, and it makes sense to carpool because of the distance. Let's talk about those hazards- First off, this is an altitude dive. The surface of the lake is at about 6,200-ft but because of the elevation gain on the way out, it's treated like an 8,000-ft dive. Second- the only access to the lake itself is via the Cleetwood trail. It's 1.1 miles down, but 11 miles up (that's not a typo- it will seem like that far). You will be engaging in some very strenuous activity after diving, which is a risk factor for DCS. There are no wheeled conveyances allowed on the trail, so you will be packing your gear out. Depending on your gear configuration, this could be 100 pounds or more. You must be in good physical condition to do this dive. Only you can make that determination about your capabilities, but feel free to ask me for more information to help put the exertion into perspective.
Now that I've got the scary stuff out of the way, I can tell you that this is a very rewarding dive, and it is something that most divers will never get to experience. Other considerations:
-The drive is about 3 hours from Eugene.
-Although we dove air last year, this year I'm planning on using nitrox.
-Water temps last year in September were 55 at the surface and 47 at depth. Your results may vary.
-I understand that you can make reservations to have the boat drop you off at Wizard Island, and pick you up on a later trip if there is space available. There is an extra cost for the boat ride. Being cheap, I'm going to skip it.
-There is a per-car admission fee to the park."
One tip that only took 2 years for us to figure out is to split gear- 2 sets of weights for 4 divers makes things easier. If you can share fins, so much the better. Sharing drysuits is doable, but probably a little further than I or most people would go. Steel 95s are overkill, but I'm a hoover and it's what I dive so hey. With the altitude you should figure on a shorter dive, so a smaller (lighter) tank makes sense if they're available. The hike is grueling, but it's only a mile, right? Just take your time on the way out, and you'll be fine, assuming you're in pretty good shape.
Once you've reached the bottom of the trail and recovered for a bit, I recommend diving to the right of where the boats dock- the walls in that area are more scenic than the gentle slope to the left.
Are you considering flying in just for this? The airport at Redmond (a small town close to Bend) is probably the closest commercial service at around 2 hours away, but there's a lot more flights into Eugene (3 hours) and Portland (5 hours). I believe you can stay at the Crater Lake Lodge- check the National Park website for more information. My local dive shop in Eugene is highly recommended, and can hook you up with whatever gear you need, plus nitrox if you go that route. I believe there's a shop in Bend, but I don't know much about them. If you are coming all this way, I would be shortchanging you if I didn't also recommend a dive or two at Clear Lake- better viz, water temp in the upper 30's, but wow- there's more to see, including some 3,000-year old sunken trees to check out. Hitting both would make for an excellent weekend. If you time it right in the fall, you might even be able to get a dive in with spawning kokanee (landlocked sockeye salmon) in one of the other Cascade lakes. If you're looking to make a week of it and hit some salt water, there's some shore diving to be had on our coast, but better diving is about 4-5 hours from Eugene in Washington's Puget Sound.
It's hard to say if I'd be available this far ahead, but we can talk. That's our busiest time of the year what with bowhunting, diving, etc. The last two years we were only able to do this on one particular weekend. I don't know of any dive operators that hit Crater Lake; our local shop does altitude certifications in Clear Lake a few times per year if that helps.
The shot below is from my 2010 trip to Crater:
This is from one of our Kokanee dives: