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driving to higher elevation after diving

Discussion in 'Rocky Mountain Region' started by knotical, Feb 3, 2005.

  1. knotical

    knotical perpetual student

    # of Dives: 1,000 - 2,499
    Location: Ka'u
    What are decompression illness risks when driving up through mountain passes after diving? We do this a lot in RMOyster country

    NOAA has a relevant table.
    Ascent to Altitude Table
    Note that this table is based on NOAA pressure groups, not your recreational table’s groups.

    NOAA tables here:
    No deco Air Dive table
    Residual Nitrogen Table
    caveat: These are NOAA tables, not recreational tables. Use them (or not) at your own risk. At best they should be considered only a guide.

    fwiw, I understand Blue Hole to be at 4625 feet, and Raton Pass at 7834 feet. After conservative morning dives in Blue Hole we stop in Las Vegas, NM for lunch before climbing Raton on our way back into Colorado.

    Remember your ABC’s: Always Be Conservative !
  2. RonFrank

    RonFrank Solo Diver

    # of Dives: 200 - 499
    Location: Conifer, CO
    Thanks for posting this, I'll have to study it a bit.

    I live at 9,000, so that 7,800 pass is a bit lower then where I live.

    In theory after diving the Hole, I should likely wait 24 hours before going home.. sigh..

    Rocky Mtn diving definately has some challanges..


  3. knotical

    knotical perpetual student

    # of Dives: 1,000 - 2,499
    Location: Ka'u
    What follows is my opinion as a diver, not representing my certifying agency or LDS.

    There are two ways to use the NOAA Ascent to Altitude table.

    One way would be to run all your dives on the NOAA tables (that’s why I also provided links to NOAA’s No Decompression and Residual Nitrogen tables).

    Or, you could convert your recreational pressure groups to NOAA’s.
    THIS IS NOT TESTED, but if you compare PADI’s single dive table (Table 1) to NOAA’s No Decompression table at all depths and round “up” (conservative), you’d get a conversion chart like this:


    Determine your highest PADI pressure group in the last 24 hours. Find that letter on the left and use the letter next to it to enter the NOAA Ascent to Altitude table to see how long you should wait. Other agencies’ tables would require a different conversion.
    Example: If you were in PADI’s “T as in tango” pressure group late yesterday afternoon, and you’re driving from 5000 to 8000 feet this afternoon, pretend you were a NOAA “I as in india” diver and wait 3 hours and 20 minutes. You can use part of that time to drive toward the mountains, but don’t climb more than a few hundred feet for quite some time.

    On the encouraging side, you’re almost certainly going to do a gradual ascent during your drive. On the discouraging side, you’ve probably just loaded a bunch of stuff into your car and we all know that exercise increases DCS risk. So, take it easy. (ABC)
  4. knotical

    knotical perpetual student

    # of Dives: 1,000 - 2,499
    Location: Ka'u
    If you dive conservatively your last 24 hours (say PADI O or NOAA G), you could (I think) still rise 5000 feet (from 4000 to 9000 or Blue Hole to your home) with a wait of just over 3 and a half hours.
    The more aggressive you dive, the longer you wait, but you should never need 24 hours from the Hole to 9000. Remember that the numbers across the top of the NOAA table are the increase in altitude.
  5. Wijbrandus

    Wijbrandus Manta Ray

    # of Dives: 200 - 499
    Location: Denver, CO
    Of course, in a training situation, it always seems like twenty-four hours pass between the time you get out of the water and you get on the road anyway...

    I don't know of a single LDS in my area that doesn't cross Raton pass within a few hours of training dives in the Hole. Then again, if they were hitting the bottom of the Hole, I don't know what their procedure is. I've only done OW at the Hole, and there were no problems returning.

    Frankly, the trip home from Homestead bothers me more. I always take I-70, but I've got like four hours (guesstimate) before you start the climb up.
  6. drbill

    drbill The Lorax for the Kelp Forest Scuba Legend

    # of Dives: 2,500 - 4,999
    Location: Santa Catalina Island, CA
    Sure makes me glad that I live half a mile from, and only 200+ feet above, my favorite dive site! The question did come up recently though about a dive group flying out of our Airport-in-the-Sky (elevation 1,600+ ft) after diving Casino Point.

    Dr. Bill
  7. octotat

    octotat Solo Diver

    # of Dives: 200 - 499
    Location: Chattanooga, TN
    I've been using the following dive table from Dive Utah (an excellent site about all the Utah diving locations BTW) and it seems to keep me alive.


    It may be similar to the tables discussed elsewhere.

    Note that you use the max altitude that you would be at within that day following the dive in the bottom time adjustments. Want more bottom time, stay at the altitude of the lake till the next day.
  8. Dive-aholic

    Dive-aholic Dive Shop

    # of Dives:
    Location: North Florida - Marianna area
    I dive and drive all the time. There could be anywhere from an hour to 4 hours from last dive to drive depending on how much packing we have to do (day trips v. camping trips). The drives take anywhere from 2-4 hours before we hit a major elevation change (>1000ft). This will be after 2-3 dives in the morning. I think the gradual increase lessens the risk. I haven't had any problems yet.
  9. knotical

    knotical perpetual student

    # of Dives: 1,000 - 2,499
    Location: Ka'u
    Thanks octotat. That is the standard altitude dive table, used a little differently. (If you’re going to eventually climb to a higher elevation, plan all your dives as if you’re already there.) Elegant and simple.

    So we now have three table-based methods, each with their own degree of conservatism and convenience.

    What about computers? The beauty of octotat’s method is that we can apply it to computers that allow you to manually set an altitude (or conservatism) setting. Does anyone know of other methods to use with computers?
  10. Rickster

    Rickster Divemaster

    Hi Everyone,
    When we finish our training dive's at the Hole, we always tell students to wait 2 to 3 hours then go ahead and drive. So, by the time they hit the pass, it will be a good 5 to 6 hours later. Also, there is a 1000 ft climb, right on I-40, immediately after leaving Santa Rosa. Next time you go there look back towards town when you are leaving. If you haven't noticed before, you will be surprised! Better safe than sorry! Thanks, Rick

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