First-hand account of down current, with video footage

[Quero]

My point is these currents never last long, and are pretty narrow. Personally, I prefer to have something to hold on and to stop me from getting deeper that to go over the blue and hope I get out of the down current before I'm too deep and out of air. But this is only my opinion, and I'm not trying to convince anyone. Do as you feel is best for you

The problem, Bison Ravi, is that you are beginning with an incorrect premise, which I've bolded in your statement. These currents are often narrow and sometimes of short duration, but conversely, sometimes they are not. For example, My own most difficult experience with a down current was along a wall that dropped down from a reef flat. When the outgoing tide reached the point where it was pulling water down the wall, it did so for the entire length of the wall--nothing narrow about it. It was like being under Niagara Falls, in the middle section. Additionally, it would have done no good at all to just hang on and wait it out--an outgoing tide may take hours to complete its cycle. In this case, I actually did climb the wall rather than swim away from it, but I did this because I knew that the outgoing tide also produced a swift surface current that would pull me out into the open ocean as I ascended if I swam away from the wall.

My point, Bison Ravi, is that we can have several strategies for coping with a problem underwater, including how to escape a downwelling, and that we will need to evaluate each situation according to its unique characteristics. It's critically important to understand the typical conditions in areas that are prone to downwellings and washing-machine currents--ones that are isolated often occur at specific places due to the topography of the dive site and can be briefed. Others, like the one I described above, are generalized and can also be briefed. And yet others may seem more random, but most certainly can also be briefed in areas where they tend to occur. As a diver, you can insist on getting this information from your dive leader during the briefing. If the information isn't offered spontaneously, just ask about it!

[vladimir]

My own most difficult experience with a down current was along a wall that dropped down from a reef flat. When the outgoing tide reached the point where it was pulling water down the wall, it did so for the entire length of the wall--nothing narrow about it. It was like being under Niagara Falls, in the middle section. Additionally, it would have done no good at all to just hang on and wait it out--an outgoing tide may take hours to complete its cycle. In this case, I actually did climb the wall rather than swim away from it, but I did this because I knew that the outgoing tide also produced a swift surface current that would pull me out into the open ocean as I ascended if I swam away from the wall.

Thanks for this, Quero. I was going to cite tidal currents as an objection to Bison's theory. Here's an excerpt from another Undercurrent ARTICLE about a tidal up-current in Palau:

I grabbed onto anything I could and hung there upside down on the wall flapping like a flag. I was cutting my ungloved hand, so I tried to put the other one on. It is very difficult to hold onto the reef with one hand and put on another glove. I jammed my fins into the underside of a ledge and let the current push me up against the ledge. I looked up and saw my wife clinging to the reef at 55 feet. She was trying to climb down my way upside down, hand over hand in the current. The current kept flooding my mask and trying to rip it off. My wife lost her mask and her regulator but was able to recover both. Hanging onto the reef, we gathered our wits and walked up the reef on our hands. Sometimes whatever I grabbed would break loose. This was one time I wasn’t worried about the reef. Once we were over the lip of the reef at about 40 feet, the current was somewhat less, but still stiff and still going up. We hung out there by hanging onto the reef, but that was as shallow as it was going to get. We sat there until we were down to 700 psi and then let go. We headed up fast, trying to fight it by kicking down, but we both popped up way too fast, with my computer beeping all the way.

[wunderhorn]

I watched the video....it is indeed disturbing. I was diving in Cozumel on 3/28 and did a morning dive on Santa Rosa on 3/29. I wrote in my dive book "terrible dive" but did not have the same type of experience. Our dive operator (AlexScuba) did not put us in right on the wall, we went in on the shallows and over the wall together, as a group. MY opinion here: this is KEY for newer divers. I was doing a dive that was part of my divemaster training so I was quite alert to the dive conditions on 3/29. There were a few newer divers in our group and a few experienced divers. We were on the wall for about 10 minutes when I saw Alex Oliver look up and I knew things were changing. He signaled for us to move close to the wall. Soon after we went up and over----we had to stay very close to the sandy bottom and it was a difficult swim back to the shallows. Due to the heavy finning the dive was shorter than normal ~ 42 min vs. usual 1 hour. However, because of the ALERT divemaster we did not have a "panic" situation. I called it a terrible dive in my logbook, but after seeing the video I realized it was only a "uneventful" dive. Stay safe out there my friends!

[Ayisha]

Quero and Vladimir, I suspect that if you translate your comments into French, it will make more sense to Bison Ravi. Sorry that my French is terrible and can't help...

[vladimir]

Quero and Vladimir, I suspect that if you translate your comments into French, it will make more sense to Bison Ravi. Sorry that my French is terrible and can't help...

Quelle honte! Mon francais est probablement pire que la votre.

[supergaijin]

Double post

[Bison Ravi]

Quero, I pretty much agree with your post, just want to clarify: In the quote you put in bold, I'm talking about the currents in cozumel, not some tidal current in a channel.

The problem, Bison Ravi, is that you are beginning with an incorrect premise, which I've bolded in your statement. These currents are often narrow and sometimes of short duration, but conversely, sometimes they are not.

With the same logic I could say down currents don't always become weaker away from the wall soon enough to let you ascend normally.

It is not a theory, it's a fact that the current is always less strong if you get closer to the wall. Like many of you said, if you get away from the wall the current will stop descending at some point. You can move laterally from a down current and most of the time you will get out of it.

There is many different kinds of currents, and many things you can do about them, it all depends of the situation.

I'm just saying very often, just getting close to the wall will help enough to get out of the situation. In the video we can see there is a lot of current, but it definitely looks manageable, and it doesn't look like it's strong enough to rip your mask/regulator off.

I'm not trying to sell a new technique or trying to convince anyone that getting close to the wall will help everyone in all cases, or that it cures cancer. But I do know that it works, and I think it is a good thing to keep in mind.

[supergaijin]

I have never experienced a strong current that suddenly became weaker in 5 mins. I wouldn't like to bet my life on it either. 5 mins is plenty of time to blow for people to run

OOA

if they're stresses and overworked.

My point, Bison Ravi, is that we can have several strategies for coping with a problem underwater, including how to escape a downwelling, and that we will need to evaluate each situation according to its unique characteristics. It's critically important to understand the typical conditions in areas that are prone to downwellings and washing-machine currents--ones that are isolated often occur at specific places due to the topography of the dive site and can be briefed.

I have seen briefings ignored more than a few times by divers who have done 100 or so dives and who have dived in currents etc. blah blah who dismiss the advice of the local guide because they've already experienced current in a few other places. One guy was a member of the Dutch royal family and had been diving for 25 years and had dived in currents much stronger and had dived this and that and the other. All well and good but the current on

this reef reacts in this way when it reaches this speed. And the guide knows because he dives on it every week.

Different bodies of water react in different ways- temperature inversions, salinity levels etc. In some locations you can actually observe the changes in the water as shimmering or other disturbance. The cloudy water at the start of the OP's video indicates something like that. My point is that currents can and do behave in strange ways and as we have only a very limited 'big picture' of the divesite overall, it's very difficult to visualise ourselves in it as we are tiny and insignificant compared to the millions of liters of water that are surrounding us on any given dive.

I've often wished for a computer simulation that can show current and how it flows around the contours of dive sites. I think it would eb a great learning tool.

As other posters have mentioned- it is usually best to move out away from the wall to avoid current if it is flowing over the top reef and then heading down. The waterfall analogy is a good one. This requires blue water ascents and early deployment of the SMB as you can travel a looooooong distance if you're doing a safety stop in currents that strong. Of course if you're shore-diving, you're on your own and must use your best judgment.

[Bison Ravi]

Another thing to consider: If you are going to dive somewhere known for it's strong currents, there is a good chance things are going to be a bit crazier around the equinox.

[supergaijin]

It is not a theory, it's a fact that the current is always less strong if you get closer to the wall.

I disagree.

When drift diving going left to right, the current is weaker due to the friction of the wall. This is the usual situation when we're doing drift dives: start at point A and finish at point B somewhere down the reef. A diver drifting 1m from the wall will travel at one speed and a diver 2m from the wall will usually drift faster.

A down current is a body of water that's moving from the shallows down to the deep. This happens on beaches with waves but usually on a small scale and so you don't feel it- maybe a slight sucking sensation on your feet if you're standing in the sand. If you move away from the shore a meter or so, you don't feel this anymore- because it's not there. The downward movement of water is closest to the beach.

When it happens like in the OP's video, the flow of water is 'usually' sticking very close to the reef as the 'down curent' is trying to slide under the main body of water. If you were very very small (like the size of Nemo), you could move from rock to rock as you move up the reef. We use this technique if possible to 'leapfrog' in to a current to get to the front of the reef where there is often a lot of big fish action. Otherwise it's 'usually' better to move out away from the wall to get back in to the main body of water and then ascend.