Rockslide/Tsunami at Antelope Point

[ScottF]

Makes you wonder, I would think that excavator would have a rock hammer attachment to facilitate the earthworks. If so, how much that hammer vibration attributed to this?

I understand that they were blasting on the cart ramp and this caused the unintended rock fall.

 

[Michael Pyle]

correct. The blast was not near where the rock fell off the wall. So I doubt there was any equipment close to the edge. Does make you realize the wall is not stable and can come down at any time.

Mike

 

[Ryan]

I’ve watched the videos several times. The boats sure are rocking, but I can’t really see a huge wave on the walls. What am I missing?

Is the consensus that AP is responsible for the slide?

 

[Ed_on_WD]

The video of the rocking boats is from the uplake end of the slips. In one of the views, you can see the second line of slips.

The rockfall occurred on the downlake side of what used to be the main pedestrian and cart ramps, where there is only a single line of slips for the rentals and the dry storage boats. The fishing dock, restaurant complex, and the fuel docks were in the direct line of fire of the big wave. The videos were apparently shot closer to the Valet Ramp, between a 1/4 and a 1/2 mile away.

If the fuel dock or the back side of the restaurant had cameras, they had the best view. The small craft slips behind the restaurant were probably subject to the most damage, as they were the closest vessels.

Can anybody call up the Antelope Point Webcam from the time of the cliff collapse?

 

[Michael Pyle]

Our Axopar was parked in the inside of the wake board park. It was pretty close. It took some hits and rubbed the rub rail bad but no damage. APEX is paying for the damage on our houseboat. So at least for now they are taking responsibility.

If you want the video of the wall you can see the wave go up and down about 3 ft and it looks to be to be all least 100ft peak to peak, which is massive.

Mike

 

[TR.]

Our Axopar was parked in the inside of the wake board park. It was pretty close. It took some hits and rubbed the rub rail bad but no damage. APEX is paying for the damage on our houseboat. So at least for now they are taking responsibility.

If you want the video of the wall you can see the wave go up and down about 3 ft and it looks to be to be all least 100ft peak to peak, which is massive.

Mike

Not to derail but if you had got the cross cabin instead of the Sun top you wouldn’t need a houseboat

 

[Michael Pyle]

TR

Tell that to my kids and all their friends that come with us on our houseboat. Not sure I want 20 people sleeping and eating on a 37ft center console with one tiny toilet. Haha

The Sun Top is perfect for us. We use it as a tour boat to enjoy the lake for the day. being open cockpit lets us enjoy the lake. Personally I look at the Cross Cabin and think too bad they are locked in a box while we are on the lake.

The ST is also perfect overnighter for my wife and I if we want to go out on the lake with our cruiser buddys and just do a overnight.

They make different models for different missions. We are so so happy with our Axopar.

Mike

 

[The Oracle]

Happy to see they are making progress on marina access. Imagine the equipment operator's stress level?! As part of the job description; "Must be comfortable wearing a life jacket at all times." What the?!?!?!...lol. Kidding aside, there's nothing particulalrly unusual about spalls, slides, etc. of that magnitude when excavating joint-controlled and surface-weathered strata. Clearly damage control may be another matter altogether. Just grateful no one was injured and wish them Godspeed in getting the access ramp back open. The Pointe has the best G&T's! Thanks to all for posting the videos and whatnot.

 

[Kevin G]

Haha just your average day in the slips at Halls Crossing! Gotta have three or four cocktails just so you can walk straight on the rockin' and rollin' docks at Halls.

 

[Michael Pyle]

It’s interesting the comments about this on here and Facebook.

I don’t think many people understand the significance between high frequency waves and low frequency. This event was a very low frequency event Unlike anything else you have seen on the lake.

Wind induced waves are higher frequency and have shorter wavelength (peak to peak) even in storms the waves at Powell are usually no more than 20-30ft from peak to peak.

This was incredibly low frequency and looks to be 125ft from peak to peak.

So normal waves at Powell are mid and high frequency like the speakers in your car door. And this wave was the subwoofer on Back to the Future.

From a energy standpoint this event was magnitudes larger than any wave you have felt at the dock


Mike

 

[Ultrastrand]

I understand that they were blasting on the cart ramp and this caused the unintended rock fall.

So they were blasting at 5:30 am?

 

[Michael Pyle]

Yes they did a small blast just after 5am up the path a ways away from the edge. The rock slide did not happen for 15 minutes or so after that.

Not sure why they thought it was a good idea to blast that early. But it was a small blast.

The rock that went was probably going to go at some point anyway. Glad it went now than when I was driving a cart on the new path. Haha

Mike

 

[Ultrastrand]

Yes they did a small blast just after 5am up the path a ways away from the edge. The rock slide did not happen for 15 minutes or so after that.

Not sure why they thought it was a good idea to blast that early. But it was a small blast.

The rock that went was probably going to go at some point anyway. Glad it went now than when I was driving a cart on the new path. Haha

Mike

Wow I have never seen anyone other than cart employees show up before 7 am. Must be an outside company!!

 

[The Oracle]

HA-Ha M1V1=M2V2... KER-SPLASH!

 

[Rainbowbridge]

It’s interesting the comments about this on here and Facebook.

I don’t think many people understand the significance between high frequency waves and low frequency. This event was a very low frequency event Unlike anything else you have seen on the lake.

Wind induced waves are higher frequency and have shorter wavelength (peak to peak) even in storms the waves at Powell are usually no more than 20-30ft from peak to peak.

This was incredibly low frequency and looks to be 125ft from peak to peak.

So normal waves at Powell are mid and high frequency like the speakers in your car door. And this wave was the subwoofer on Back to the Future.

From a energy standpoint this event was magnitudes larger than any wave you have felt at the dock


Mike

View attachment 19217

Mike, Thanks for that explanation of low vs. high frequency (and of course the neat pic) The magnitude of the power explains the movement of the boats/dock and the damage.....(and thanks for the vids)

Question: When a wave of this much power hits the other walls, does it bounce back like other waves behave, say in Maytag?.....guess I'm wondering if the 'bounce back' wave was also a problem?

 

[Michael Pyle]

Thats a good point. I bet the wave kept going all thru the lake and made a huge mess in the canyons. Good thing it was 5:30am. Would love to see what it looked like after a few corners and it got all confused in the channel . That much energy does not go away easy. I bet the energy was like 5 tour boat waves.

Would be fun to see.

Mike

 

[Line]

Wow that’s impressive! It reminds me of this video of the valet ramp getting constructed. I always wonder if the docks are designed to flex like that, or if they made a mistake by installing them before the blast.

 

[Michael Pyle]

Oh wow. That’s a crazy video. That’s way larger and yeah nuts they did that with the dock in. Can’t believe how much it flexed.

Thanks for sharing.

Mike

 

[Bill Sampson]

I’ve watched the videos several times. The boats sure are rocking, but I can’t really see a huge wave on the walls. What am I missing?

Is the consensus that AP is responsible for the slide?

I also did not see the huge wave.

 

[Michael Pyle]

Bill,

If you watch the YouTube video and focus on the wall you will see the rise and dip of the wave series. It’s not super tall. Maybe 3ft but it’s long.

Mike