Girl dead, boy injured - Lake McDonald, Glacier National Park

[rsingler]

Can't speak to the death, but it's a bit of a setup for DCS, isn't it? Divers are warm on descent with good ongassing. Maybe colder on ascent, with some vasoconstriction and impaired offgassing. Add in some physical effort scrambling up a slope with gear if there's no infrastructure, which facilitates bubbling along muscle shear planes. Then top it off with surfacing to a decreased ambient pressure that increases the gradient (even if stops were lengthened).
Not sure this would be my favorite place to deep dive. At least Lake Tahoe, despite 6,000', has an easy stroll off the beach, and the temps are warmer.

@boulderjohn ?

 

[Raphus]

If not for the chamber then it would seem like bad air.

I think some bad air situations can lead to a chamber ride aswell.
I know for sure, that smoke inhalation, during a fire, is cured in a chamber.

 

[DandyDon]

I think some bad air situations can lead to a chamber ride aswell.
I know for sure, that smoke inhalation, during a fire, is cured in a chamber.

Yes, for carbon monoxide which is what smoke inhalation poisoning is as well as a risk with any tank. My view is that any untested tank is a risk, but that differs from the leading money makers in the industry.

The girl's obituary tells about her scuba and travel background: Linnea Rose Mills Some childhood schooling in Bhutan, Scuba certified in North Carolina at 15, exchange student to Austalia who dived the Great Barrier Reef at 16, 7.000 mile solo camping adventure around the western US, etc. Certainly an admirable young lady with much to share with the world, but sadly her adventures caught up with her.

 

[Bob DBF]

..carbon monoxide which is what smoke inhalation poisoning is...

Although I completely agree with your war on CO in scuba tanks, there are more, and more toxic, chemicals that can be in smoke, dependant on what is burning.

"Smoke inhalation is the leading cause of death due to fires. It produces injury through several mechanisms, including thermal injury to the upper airway, irritation or chemical injury to the airways from soot, asphyxiation, and toxicity from carbon monoxide (CO) and other gases such as cyanide (CN)."

 

[boulderjohn]

Can't speak to the death, but it's a bit of a setup for DCS, isn't it? Divers are warm on descent with good ongassing. Maybe colder on ascent, with some vasoconstriction and impaired offgassing. Add in some physical effort scrambling up a slope with gear if there's no infrastructure, which facilitates bubbling along muscle shear planes. Then top it off with surfacing to a decreased ambient pressure that increases the gradient (even if stops were lengthened).
Not sure this would be my favorite place to deep dive. At least Lake Tahoe, despite 6,000', has an easy stroll off the beach, and the temps are warmer.

@boulderjohn ?

I don't see any information on the dive plans, so I cannot even make a guess as to this specific case.

Cold water diving does bring on a greater danger of DCS for the reason stated above. You are usually more active and warm during the early part of the dive, when you are on-gassing, and you are usually less active and colder at the end of a dive, when you are off-gassing. That affects your blood flow (perfusion), and blood flow affects both on-gassing and off-gassing--the better the blood flow, the better nitrogen is transported. When you really start to get cold, the body restricts blood flow to the legs and arms in order to maintain temperature in the body core. In a traditional, table-based OW class, students are taught to plan cold dives as if they are 10 feet deeper than they actually are. Many decompression divers perform light exercise during long decompression stops to stimulate blood flow.

This is, however, normally only a matter of true concern in decompression diving, and I have seen no indication that his was happening. In NDL diving, the ascent time is not long enough to have it be a truly significant factor. For a person to die on the spot due to DCS, it would have to be a very serious case, such as person going straight to the surface while having a major decompression obligation. I would be surprised if DCS were the cause in this event.

A joint PADI/DAN study of dive fatalities (other than medical events) found that the most common cause was a lung overexpansion injury, specifically AGE. This can happen with a rapid ascent while holding the breath. A lung overexpansion injury can also cause difficulty breathing that would be treated with a recompression chamber.

As for altitude, the altitude of that lake is not likely a factor.

 

[Bob DBF]

As for altitude, the altitude of that lake is not likely a factor.

With the rare exception of a recreational diver using tables, and not correcting for altitude, and the rare exception of a recreational dive computer not automatically correcting for altitude, it would be nearly impossible for altitude to be a factor in a recreational dive today.

 

[boulderjohn]

Here is another comment about cold water diving, aloing, with an emphasis that I am NOT speculating on this incident, because I know nothing of the dive profile or other related factors.

The elements of her biography mentioned above do not mention any cold water diving experience. Having worked with a number of students in their first COOL water diving experience, I am well aware of a common skill-related problem that is normally ignored in warm water diving. I emphasize the word COOL, because I am talking about 60° water, much warmer than what is described in this incident. The divers I am talking about wore a 7mm full suit. Divers in colder water would often wear a another layer of at least that thickness. That takes some getting used to.

The problem is that the amount of weight needed to make the initial descent is much more than is needed at depth, when the suit has compressed significantly. Divers with a very thick wetsuit have no choice but to dive with a lot of air in the BCD to compensate for that unneeded weight at depth. When the dive is over and the diver ascends, the diver must be very careful to dump air rapidly out of the BCD, especially in the last 20 feet of the ascent. With the wetsuit expanding with the lessening pressure and the air in the BCD expanding as well, this can result in an extremely rapid ascent, with the diver breaking the surface like a scene out of Hunt for Red October.

BTW, this effect is more pronounced at higher altitudes.

 

[boulderjohn]

With the rare exception of a recreational diver using tables, and not correcting for altitude, and the rare exception of a recreational dive computer not automatically correcting for altitude, it would be nearly impossible for altitude to be a factor in a recreational dive today.

For most diving, that is probably true. It starts to get dicey when you get into very high altitudes. We have people in Colorado diving at 10,000 feet. At that altitude, though, other factors, including acclimatization, come into play. The US Navy manual's warning not dive at that altitude without proper clearance is printed in bright red, bold type. Still, at that altitude, it probably would not be a big deal if you stayed pretty shallow.

Altitude is more of a factor in decompression diving, and, again, if you use a computer that adjusts for altitude, that will help a lot. Many decompression divers, however, still do not use computers, and if they are following a plan generated by desktop software or another system that does not compensate for altitude, it can definitely be a factor.

 

[Bob DBF]

For most diving, that is probably true. It starts to get dicey when you get into very high altitudes. We have people in Colorado diving at 10,000 feet. At that altitude, though, other factors, including acclimatization, come into play. The US Navy manual's warning not dive at that altitude without proper clearance is printed in bright red, bold type. Still, at that altitude, it probably would not be a big deal if you stayed pretty shallow.

Altitude is more of a factor in decompression diving, and, again, if you use a computer that adjusts for altitude, that will help a lot. Many decompression divers, however, still do not use computers, and if they are following a plan generated by desktop software or another system that does not compensate for altitude, it can definitely be a factor.

I understand, which is why I emphasized recreational in my post, as I would consider both of your examples as technical.

 

[mariah]

I feel sorry for the girl and during diving it is impossible to help others so I guess that is why the boy was helpless and he also got injured himself. Diving is not a child game people should be more careful about it.