Diving Minnewanka -- How important is Altitude diving training?

[Token]

I am considering doing a few easy recreational dives in Minnewanka and Two Jacks Lake. No extended times or great depths...they are more for the sake of practice than anything else. Is it really important that I have the Altitude Diver specialty training? I get the sense that very few people bother, given a dive computer that can handle the conditions...

 

[Hawkwood]

Token,

You will get different opinions on this. Yes, this is altitude diving and regardless of the computer "handling the conditions", you need to understand what those conditions are. It may seem trivial to some, but even the effort of struggling with gear can take it's toll at altitude. Is formal training necessary? That is your call. At the very least, going diving with someone who is experienced diving in Minnie and Two Jack and can orient you to the sites and altitude considerations for those sites is strongly recommended. Hook up with the Underwater Outlaws for example. Many of the shops in town also do Discover Local Diving experiences. At the shop I teach through we simply ask you make a donation that goes to Project Aware.

The diving in the lakes is not to be missed, there is a lot to see and they are great places to practice. You will see lots of divers out on the weekends.

I see from your profile, that your OW dives were in warm water in Florida. Have you been diving in our cold mountain lakes yet? Although it looks so, don't be caught looking at "easy recreational dives" in Minnie and Two Jack. These are cold, low vis dives that can fool you if you are not prepared. It's not the altitude so much, but the cold and other conditions that can surprise the unaware.

I did my OW in the tropics. I had a good friend who had a lot of experience introduce me to diving in Minnie and Two Jack. I am glad I did. I had a great experience as a result and it turned me on to diving in cold water.

My answer is based on what I saw in your profile - 0-24 dives, warm water only, etc. If your profile is not up to date, you might think of editing it, it can change how people answer questions posed. Some folks look at the "About Me" to get an idea of experience, where folks have dived, etc. to tailor the answer to your experiences.

Bill

That's "my boy" at the bridge pilings in Minnie.


Cruising in for our safety stop in Minnie - 12 feet at our altitude (one of the things you should know).


Two Jack - shallow and a very silty bottom - good buoyancy and good finning techniques are a must (DMC showing how its done).


Navigating through the "meadow" in Two Jack - your compass and navigation skills need to be sharp - vis is often 15 feet or less.


Some of the "sights" in Two Jack.

 

[Jim Lapenta]

Even if you don't use a computer you do not need the specialty unless you can get it for less than say $25.00 & that includes the altitude slate from trident.

Sent from my DROID X2 using Tapatalk 2

 

[Crush]

Welcome to SB, Token,

I agree with Hawkwood and Jim Lapenta. Remember that diving tables were derived for dives which begin and end at sea level. I your case you will be descending, the surfacing to a pressure which is less than sea level. As a result of the decreased atmospheric pressure on your body at the surface, the nitrogen bubbles will have a stronger tendency to come out of your tissues than they would if you were at sea level. At the elevation of Minnie this approximately equates to a 20 foot penalty to your depth for many recreational depth dives - that is, treat a dive to 70 feet as though it were a dive to 90 feet, etc.. Most computers will do this for you, however, be sure you know how your computer works. Mine, for example, will automatically sense the elevation and adjust for it, but only if the computer is activated prior to getting wet. Also, if you drive from Calgary to Minnie you will already be over-saturated with respect to nitrogen thanks to the difference in elevation between the two sites - this over-saturation is a condition which your computer and tables will not account for. Many divers opt to take a few lazy hours in the area to decrease their N2 levels. Finally, cold can complicate DCS. If you start a dive warm and end a dive warm, you are fine. If you start a dive cold and end a dive cold, you are fine. If you start a dive cold and end a dive warm, you are fine. However, if you start a dive warm and end a dive cold you are at an elevated risk of DCS because at the beginning of the dive your tissues were well-perfused (i.e., you had good blood flow) and those tissues would have been subject to nitrogen loading as you descended. However, when you get cold the perfusion of many tissues in your extremities is hampered, resulting in a decreased ability to off-gas as you ascend. As a rule of thumb I take it easy on cold elevation dives, preferring to not "red-line" my N2 loading.

Have some great dives.

-Crush

 

[Hawkwood]

Crush,

Have Token send you the $25 via PayPal - Ha!

 

[Jim Lapenta]

Another practice is one that I was taught when doing dives at one of our semi local sites. The elevation is 3250 feet so on the tables we round to 4000. Since we often did this as a weekend we'd save deep dives for sunday. Reason being as you ascend up the mountain you need to account for that. For every thousand feet you ascend you add two pressure groups to your starting pressure group. With the SEI tables therefore at where we were diving, if we went in immediately we planned the dive as one with a beginning group of "H". However we always took our time gearing up and so would actually not enter the water for about two hours. Using table two on that meant we were now starting at pressure group "F". After 6hrs 33 minutes we were back to "A". PADI tables are a little different as to where you end up but it was after 6 hours on them we were clear. So roughly every 50 minutes we "off gassed" enough to move up a group. So by making a weekend of it and staying at altitude overnight we were fully cleared for doing the deep dives of the AOW course on Sunday morning.


But again decompression is all theoretical and so some will say it can be a bit faster and others perhaps slower. It all depends on how conservative you want to be and as Hawkwwod said a dive at altitude in a 40 degree mountain lake is going to get planned differently than the ones we were doing in a mountain lake heated by a coal fired power plant with 80 degree plus water temps. The warmest I ever recorded was 93 at the surface and 88 at 105 feet.

 

[Hawkwood]

Yeah, our temps once the ice is off will range from 36F to a max last year of about 55F. The ice is still on Minnie, but starting to open on Two Jack. Typically it will not be until our May long weekend that the ice is off sufficiently on Two Jack to contemplate some diving. Of course it often snows that weekend also - another "fun" aspect of diving here.

In the summer we can be looking at a 30 degree temperature difference between air temp and water temp. Something that has to be taken into consideration.

 

[nadwidny]

The group I dive with at Minny routinely do 1.5-2 hour dives there. We do not adjust for altitude and we do not spent hours deompressing prior to the dive. Altitude is over-rated.

 

[Hawkwood]

Brian,

I'd agree - I would suggest that more important are the diving conditions specific to the locations, which just happen to be at altitude - including all the fun stuff at the surface including the goats, busses, mobs of cyclists, some "fun" entries, etc. Big changes to happen at the sites this year as well which will ease the surface crowding.

 

[supergaijin]

I wanna dive there dressed as Mickey Mouse- I thought NZ had some bizarre place names.