I have been reminded by a few people that in my series on Loving Current Diving, I neglected to talk about down currents. Neglected would be the appropriate word. I chose not to talk about them for a simple reason. They can be scary!
The idea behind the series is to help people love on current diving, not scare them to death. However, in further conversations with myself, I realize I am doing a disservice by not sharing the information. Knowledge is power and in diving, can be life saving.
Down currents are not terribly common but there are some dive sites across the world where they are the norm. I have found strong down currents during late summer/early fall in Cozumel and also on dive sites like Peleliu Express in Palau.
Water sweeping over the top of a wall or steep slope can push downward causing a heavy current heading down to depth. It can cause an unsuspecting diver to suddenly find himself dropping quickly to depths they had not intended to go. The dangers here include going into decompression, running low or out of air and difficulty getting back to shallower depths. If you are a slow “ear-clearer” a sudden drop in depth can wreck havoc on that air space as well.
The best way to spot a down current is by keeping an eye on your environment. Generally strong down currents will occur when other currents in the area are strong, meaning lots of water is being pushed about. We would not expect a sudden strong down current simply “out of the blue” when no other current is around. Watch ahead as you travel down the reef. If you see bubbles of divers ahead of you turn in a downward direction, a down current is present. If all the little fish are pointed head up and soft corals are sweeping downward beware of what’s ahead. Just like every other type of current, down currents can be mild or strong. Usually, down currents are more of a temporary condition, meaning shorter duration, than other currents.
Personally I prefer to avoid down currents because the last thing I want is something unpredictable pushing me downward. If the current doesn’t look strong and I decide to go through it, I will ascend to a shallower depth to give myself some “breathing room”. Then I will stay close to the reef in case I need to grab ahold of something to keep myself level.
If you suddenly find yourself in a strong down current there are a few things you can do.
1. Don’t Panic. Stop, think and act.
2. Grab hold of something on the reef, preferably something not living, to stop the descent.
3. Often down currents occur in “sections” of a reef so it’s possible to swim through it and out the other side because something is funneling water down from the surface at this particular point.
4. If you’ve just encountered the current, it may be possible to turn around and swim out of it. However, you will probably already be drifting this dive so that may not be an option.
5. If the current persists, you can “crawl” up the reef hand over hand. Obviously this is bad for the reef but if the situation is desperate you may need to do it.
6. I am leery to suggest swimming out away from the reef. At some point the current will dissipate but there is no way of knowing how far you will have to go and how strong you may be pulled down in the meantime without a physical means of holding on.
7. If your situation becomes serious, you can inflate your BCD. You need to be VERY careful doing this because if the down current suddenly “turns off” you will find yourself heading quickly in the opposite direction! Be very watchful of the direction you are going and be prepared to dump air quickly.
8. Last resort is to also drop your weights. I have never been in this dire of a situation but if it’s the only option to not making it to the surface at all, I would do it.
Down currents, as mentioned above are not common. However, sites with known strong currents may frequently have strong down currents as well. Be sure to obtain local knowledge before diving and if you are uncomfortable, skip the dive.
I hope this helps you to understand down currents while still learning to love current diving!
To Your Adventures,