Insane, unpredictible current, WHY!?

[Sintax604]

I know Lookout is famous for it's unpredictable currents but last night it really screwed me.
According to the tide tables, there should have been an exchange of less that 1 foot/hour which is why we decided to dive Lookout. What we got was the strongest, most irregular current I have encountered as well as the best vis I've ever seen on the mainland (50-60' in all directions).

Can anyone explain this and perhaps provide a method of predicting it?

The water looked very calm and inviting but as soon as we dropped down, just before the point on the West side of the bay we where whisked away by the current. Knowing that current here can be unpredictable, we discussed the possibility of riding it to Whytecliff before going down. There SHOULDN'T have been any current, but within seconds of descending, we were signalling to go to Whytecliff. It was a glorious drift as we ripped along the bottom, barely having time to look at critters since we were moving so fast. Then it stopped. We came over a ridge and all of a sudden there was no current at all! We swam on for a couple minutes only to find that we were now fighting the current. After exchanging confused looks and a couple written points on strategy we decided that fighting a mild current all the way to Whytecliff would be unpleasant and probably not even possible with the air we had left, we decided to turn around and head back to the bay at Lookout.
Not surprisingly, we rode the mild current back and then found ourselves clinging to rocks in the face of rushing water trying to keep us away from Lookout. More looks, more written messages. We decided to call the dive and figure things out on the surface. We ended up surface swimming all the way to Whytecliff with current alternating with us and against us. It wasn't the least bit fun.
Finally, we made it to Whytecliff and decided to continue our surface swim over the day marker rocks and into the bay. After our ordeal we were in no mood to go home and rinse gear so we were heading for the Whytecliff shower. We dropped down (almost on top of some divers from The Edge) and made our way toward the shower. In about 20' of water we encountered mild current sucking us out away from the beach. IN WHYTECLIFF BAY!!!! There's NEVER current in the bay that close to shore!!!!!!

Can anyone explain this!??! Lookout used to be one of my favourite sites but we're breaking up and not seeing each other for a while. I'd love to be able to predict the conditions in the future. Thoughts?

 

[coldwaterlloyd]

I have encountered the same thing with currents this past year . Slack tides that do not happen , crazy currents on predicted low exchange , Urban Myth has it that the volcano in Iceland shifted the earths poles slightly throwing off GPS and predicted current tables .
Japans earthquake shifted the island 3-10 meters , I would imagine all these things could affect current / tide predictions . Again , Urban Myth .
Sounds like you guys handled the situation brilliantly without a hitch , well done .

 

[sschlesi]

Around Whytecliff, I have found currents to be stronger than usual and unpredictable around particularly high and low tides regardless of the size of the exchange. Though I don't think that applies to yesterday's tides. I have also experienced current in the middle of the bay so strong that finning as hard as I could barely managed to keep me from going backwards while plenty of seaweed and other detritus rushed by. At that time there was a strong wind blowing directly on shore, and high tide had passed an hour or so before. My theory is that the wind was pressing water into the bay on the surface, while the receding tide was drawing water out of the bay along the bottom.

 

[CR Diver]

As I have never dove in this area, this is just a opinion:
I live/dive primarily in the Campbell River area on Vancouver island. We are geographically located quite close (couple miles) to Seymour narrows which regularly has currents to +/- 15 knots, which means we get current in the 7 - 8 knott range at our popular dive sites. Because of this current, we need to time our dives for slack water. We have found that tide tables (exchanges) and current do not reflect each other. For example we mave have a 1 - 2 foot tidal exchange, but can encounter 8+ knotts of current in this area, for this reason we can use tidal exchange for rough timing of slack, but depend on current tables for actual conditions.
We are fortunate that we have multiple current stations in our vicintiy to determine proper water conditions. Unfortunately there are not any around the lower mainland, but you can look at other stations close by on the coast to determine what water levels and currents are doing on the days/nights your diving?

Here is a link to the site I use, when I'm running the Charter boat.
Currents at Seymour Narrows, British Columbia

the software we use on the laptops on the tugboats is Captain Mosaic, charting software, which will give you estimated current anywhere you point the mouse on the electronic charts - pretty good tool.
Anyways, just a thought.