DOWN CURRENTS -Any with true real-life experience?

[Seaweed Doc]

I've been caught a couple times. Both were tidally driven downwellings, and both times I clutched the bottom. And obviously survived.

The first time was in an area with whirlpools that shifted and moved with tides. There really wasn't a hard bottom until you got to 300' or so. Moving off the wall wouldn't necessarily have helped. Neither would trying to move laterally out of the current. The water motion is not consistently holding in one spot. My buddy and I pulled ourselves up the wall from 80' to 60' and at that point the current shifted and blasted us laterally. So we held on to the wall and made like rock climbers but with the current blowing us 90 degrees relative to gravity. At 30' we got caught up in a strong upwelling. I was venting from my BCD, and even so the BCD bladder was filling faster than I could vent. No comment on what other bladders might have been doing. That was probably the most dangerous bit: Rapid ascent could lead to DCS or lung overexpansion if I hadn't been blowing.

But our approach might not have been the best solution in other situations. We were in a place where moving laterally to the current might just have kept us in it as the current shifted.

The other time was a straight downwelling at ebb tide. I ended up using my knife to hold position in the mud and work gradually upslope. But this was much shallower and generally a less dangerous scenario. In hindsight, pushing away from the slope may very well have been a good solution. The site has a hard bottom at about 90', so not as much risk if you're wrong.

Long story short: I think the correct answer may depend on the nature of the current and the local bathymetry. The more you know, the better.

 

[Superlyte27]

Until you have to bail out due to a CCR issue…

That hasn’t happened in thousands of dives. I’ll take those odds

 

[Centrals]

Canyons, Horse Head and Verde Island in Puerto Galera(Philippines).
Verde Island has the strongest but if you are closed to the wall you can climb up but the other two is in open water.
70 bars is the min required to finish the dive for the first two. They are quite close to each other and at the tip of a cape where two currents meet and far away from the wall. Only those who had dived these two sites a few times would understand why operators insist on 70 bars as the bare minimum for ascent. You do not want to be caught short on down current. There is NO where to climb!

 

[txdamselfish]

Talk about Down Currents, a freediver was pushed down to 150ft in the gulf stream and came up over a mile away.

Watch the unbelievable moment a Key West family found their missing son lost at sea

Priscilla Gartenmayer's TikTok of the moment her family spotted her missing cousin, 22-year-old Dylan Gartenmayer, has gone viral.

news.yahoo.com

 

[MBTS]

I've had the same experience a couple of years ago, quite possibly on Santa Rosa.

Pre-dive, the DM warned us about the possibility, and specifically said that we should look out for areas at the edge of the top of the wall where sand was being swept out/down. I saw a couple of spots like that, very much like a 5' wide hourglass -- a sandy depression that became a steep funnel, with sand visibly flowing downward from the current.

Knowing what to look for helped people stay away from the edge of the wall, and there were no issues.

I've experienced similar in Cozumel several times. A sudden decrease in visibility, debris rotating in a circular motion similar to a vortex, and a shift in the current pushing away from the wall instead of along with the wall are what I remember clearly.

 

[Bigbella]

Google "scuba downcurrent" and "scuba down draft" and you'll find come conflicting advice; some say inflate and kick up, while others (like DAN) say be very careful about inflating because uncontrolled ascents can be the consequence. Think of the current as a vertical riptide; it is hard to swim against it, but you can maybe swim sideways to get out of it...bearing in mind that it might be wide (along a wall, for example) so the bes swimming direction is away from the wall. My game plan on a wall dive is just to hang onto the wall (using dead things if possible)...and try and move sideways if possible.

What is very odd about those "down currents" is that they seldom exceed more than two knots; but it is definitely humbling that swimming against them seem almost an impossibility.

The Gulf Stream off of Florida, only averages about 3.5 knots, headed North -- and even that seems very gradual, during a relaxing drift dive off of Jupiter, until one attempts to swim against it.

In terms of a fierce down-current, I have only experienced it once, in the Coral Sea, around 2001, near an outer reef, and felt pulled, arse-backward from about thirty to forty meters. What it took to finally combat it, required a hand-hold on the reef and a plodding mostly vertical climb along the wall -- feeling, all the while, like a flag in the wind.

There was an interesting account in Kevin Fong's Extreme Medicine: How Exploration Transformed Medicine in the Twentieth Century, where he was caught in such a current, near Fiji, if I recall, and his colorful and panicked visualization of his blood "frothing" nitrogen was particularly memorable -- consuming, as he mentioned, about a half liter per breath early on, during the dive, then about five times that volume, while fiercely swimming against the current, coupled with his "Nothing in my knowledge of dive medicine was particularly reassuring" comment, in terms of avoiding some form of barotrauma, after extended periods of physical exertion at depth . . .

 

[bubblemonkey2]

in Deception Pass in Washington state. But that's certainly not a basic dive. There's supposedly an "underwate waterfall" in the Tacoma Narrows, but I haven't hit it the few times I've drifted through there.

I would be interested to hear more firsthand accounts of downcurrents here, to understand where & when they specifically occur.

The bottom of Deception Pass itself (anywhere near the bridge) bottoms out at only ~40 metres / 130ft, probably because the rock is too solid for deeper erosions. Within +/-15 minutes of the true slack, a full flush to the bottom is survivable for a non-panicked diver--but few divers are going to remain 'cool' when that happens. And an open water ascent there at slack time puts you right into a traffic jam of powerboats trying to sneak through the pass on slack

If you end up blown outside of the pass itself, max depth is around ~60 metres in spots, certainly hazardous for most divers. There is very nice depth data here (uncheck everything except "BAG Color Shaded Relief")

I've heard there is a "geyser" just beyond(?) the bridge position, caused by water constriction that can blow a diver to the surface near the end of the flood tide (just before we typically aim for the 'North Beach' entry). I have yet to experience it directly.

[Probably] significantly beyond that I once encountered an ascending ramp feature at ~25 metres depth, which led me to cling on for 10 minutes (waiting for slack to finally occur) before rock climbing back down to 30m+ to get out of the upwell. Fortunately had time to stop, assess, and backtrack on a rebreather.

 

[bubblemonkey2]

Until you have to bail out due to a CCR issue…

Another thing that can catch us by surprise on CCR is a rapid reduction in loop volume due to a sudden/strong descent.

If you had proper minimum loop volume at the onset, then you now can't breathe, and are struggling to restore it via the ADV or MAV.

Or worse(?), you might have had excess loop volume, and you can still breathe at twice the depth, except your ppO2 is now 2.5+. And you will likely fail to notice or be able to flush, since you are already busy freaking out

 

[bubblemonkey2]

I've run into them a handful of times in British Columbia. In one case, I hit bottom in about 140' but pretty had to climb up the wall. In another, the water was much deeper (300+) so I juts added some air to my drysuit... Like many things in diving, they're generally manageable with a minimum amount of fuss if you don't over-react.l

Ever since I dived the God's Pocket area, I wondered about how amazing some of the deep wall tech/CCR diving might be. But recently I was told by good source that there have been serious & fatal accidents in this context, due specifically to downcurrents.

 

[jont2]

Beach 8th Street in NYC has "down currents" regularly because of the underwater obstructions and strong currents, Its never killed a diver but it has killed several swimmers over the years.