First off, let me point out that we're all speculating that the current had anything to do with this accident. That said, the chances are pretty good that it did, given the time of the accident and what was going on with the tides at the time. I'll give some info on the Redondo River, based on over 500 dives at this site over the past nine years ... since I moved into a house just a couple miles from there.
As AWAP just posted, the site lies within what might be roughly considered a cove ... between Dash Point to the south and Three Tree Point to the north. The site is bracketed by two wide, shallow beaches, north and south. Between those beaches lies the main part of the dive site, as well as the fishing pier and boat ramp ... which are distinguished by a relatively steep dropoff from about 15 foot depth (at mean high tide) to about 90 feet. Below 90 feet, the bottom shallows out again ... you can reach 90 feet in a hurry at this site, but then it takes a pretty long swim to reach 100 feet. Because of this topography, the site can exhibit some strong currents as the tide pushes water through the area, across the shallow beaches north and south, and that water then rushes down the steep sections into what can best be described as an underwater waterfall. No matter which direction the tidal flow is going, one part of the site or another will experience this ... but how strong it will be depends not only on the size of the tidal exchange, but the rate at which the tidal change occurs. In other words, looking at a current chart, it will depend on how steep or shallow that slope will be. In this respect, it's not as simple as looking at a tide map to determine whether or not this is going to happen.
When you hear people talking about how this happens on an ebb, understand that it happens on both an ebb or a flood ... but it affects different parts of the site. Water flowing in on a flood sweeps around Three Tree Point on the north, flows toward Dash Point in the south, and the part of it that hits Dash Point sweeps back in an eddy along south beach, and down the steeper sections of south drop-off as it approaches the dive site. Divers on the south side will experience downwellings on a flood. But because the dropoff is less steep on that side ... and most people don't dive on that side ... it's less noticeable. The majority of people enter at the stairs between the fishing pier and aquarium, and dive on the north side, where the dropoff is steepest and the effects of the downwelling can be, at times, overwhelming. On an ebb tide, water flows around Dash Point, sweeps along the shallow south beach at a pretty good clip (because it's shallow), hits the dropoff and turns west ... going downslope into the deeper part of the site. Effectively it's creating a "waterfall" at depth that pushes divers down the slope ... sometimes dramatically so.
Now, some things to keep in mind ... the majority of the time this dive site is quite benign. Several dive shops, as well as several independent instructors such as myself, teach classes there regularly. The beach north of Salty's is particularly suited to classes because it's shallow for a long way out, and because people have dropped "junk" in the water that tends to attract creatures like fish, crabs, and octopus ... which live in 40 feet or less of water. So this is an ideal site to take new divers to experience these creatures. But those who teach there know when to schedule classes ... and when it's prudent to consider a different dive site, because on this side the current won't take you down but it will sweep you north along the beach and away from the entry/exit area. One always has to be cognizant of what the current's doing, and get your students out of the water if it starts to kick up. The other thing to keep in mind is that it's usually transitory. A strong current can last from a few minutes to as long as a half hour ... and then it dissipates down to something that's barely noticeable. Those of us who are there regularly have been known to get our students out, wait a reasonable surface interval, and go right back in again. You can often tell by watching your buoy what the current's doing ... but I've seen it strong enough there to almost overpower a scooter, much less a diver.
Generally speaking, the current will be worst along the dropoff area, where it tends to want to push you downslope. If a diver is caught in that, the best solution is to get down close to the bottom. If there's something to hold onto, hold on and wait it out, assuming you have adequate air. If you don't, try to make your way to one of two ropes running upslope to the top of the dropoff and pull yourself upslope. Failing that, dump all your air and belly-crawl upslope. Even I've had to resort to all of those at times ... and I've got pretty strong skills when it comes to dealing with current.
A newer diver, one inexperienced in this current, could easily find themselves overwhelmed by the sudden onset of this, particularly if they're at depth with a dwindling air supply and trying to make their way upslope. Fighting the current rather than grabbing ahold of something or doing the "belly crawl" could quickly deplete their air supply. And if they're in something like this, it's questionable that a newer diver would be in any position to render assistance to someone who's out of air ... particularly not with a standard recreational regulator that has a relatively short hose, and is designed to be deployed such that two divers sharing air are pretty much forced to make a vertical ascent. Such an ascent simply isn't possible when you have a strong current trying to push you down and away from your exit point. This could possibly explain why the buddy wasn't able to render assistance ... he had neither the skills nor gear to do so effectively. Again ... take that as speculation, because I do not know that to be the case ... but it could explain the situation. It would also explain why he was able to go back with the rescue divers, locate the victim, and assist in her recovery shortly after the accident ... because by then the current would've moved on.
For those objecting to the term I used ... this site has a very silty bottom. Improper finning technique ... or this current, when it's running stong, can turn visibility to close to zero at times. More often, it will pick up objects and send them tumbling downslope ... crabs, starfish, or during the summer months, sea lettuce. This can also impact visibility. I wrote a story about such an occurrance at this spot a few years ago called Miso Soup ... you can find it on my website ...
NWGratefulDiver.com
Another potential problem is that many of the features at this site are in areas that are very silty ... and with improper finning technique are easily blown out. For those objecting to the term "mudhole", an errant fin kick in the bottle field ... one of the more popular attractions that sits at between 75-90 feet ... can sufficiently stir up the bottom to cause you to lose your sense of direction. This area is relatively flat, and one of the big dangers here is when vis is poor it's easy to get turned around and be kicking away from shore when you think you're heading in ... entering an area called "the trough" that slopes up on both the in and out directions. Paying attention to compass headings then becomes very important ... or one can find oneself far from shore with a dwindling air supply. This is but one of several potential "gotchya's" that could cause problems that can lead to an OOA here.
Well, that should be enough to give you some mental images of what you're dealing with. We generally advise less experienced divers to avoid the deeper parts of this site, below the dropoff. But there are attractions down there that people want to go look at ... like a wolf eel living in a tire, an old boat where a giant octopus lives, and a few others. So they go there anyway. And as long as nothing goes wrong, they're OK. But when things do go wrong, there's a potential for them to go very wrong. This appears to be one of those times ...
... Bob (Grateful Diver)
