Buoys are generally tethered to the bottom - letting them float freely could be a hazard to navigation. There are some that do, but most buoys need to stay in pretty much the same location over time. Even those that are anchored may move, depending on the type of anchor - a large concrete weight is common, although if the depth and sea floor type permits, a buoy may be bolted to the bottom.
The tether may have some give, but in extremely high wave conditions, the buoy may run out of tether and wind up submerged.
Buoys (at least National Oceanic and Atmospheric Administration buoys in the U.S.) measure wave height through internal accelerometers and inclinometers. GPS can sometimes give sufficiently accurate elevation information, but does not work at all when the buoy is submerged.
This was the record for largest wave measured by a buoy. In the same article, it mentions a surfer who rode a 78’ wave, so 70’ is certainly possible. Of course, that doesn’t preclude the possibility that the height of the waves from the OP were exaggerated, which is very likely.
Interesting. I didn’t realize there were moored buoys in such deep water (and, presumably, very far from the nearest shore). I assume that skilled mariners know to look out for them so they don’t get run over by a supertanker or something.
Waves build up and break as they get to shallower water where the surfers hang out. Comparing a mid-ocean swell to a breaking wave at a beach is not really the same thing.
I once saw a Lake Michigan weather buoy report a 255-foot wave, followed by a zero wave height. Since a wave that large, if it came ashore, would have inundated my house with 200 ft of water, and that didn’t happen, I’m inclined to think this was a single byte digital sensor that went nuts, and reported all binary ones for an instant.
Which won’t stop me from looking out the window if it happens again.
Other large waves reliably measured: [ul]
[li]The rogue wave that struck the Draupner Platform on 1 January 1995, and was measured at 84 feet high with a laser heightfinder. That platform is roughly 90 miles off the shore of Norway, in about 230 feet of water.[/li][li]Depending on your belief in the crew’s trigonometry abilities, the wave that SS Ramapo encountered in a massive storm in the Pacific Ocean on 7 February 1933. A bridge officer calculated, based on sightlines from the stern and crows’ nest, that the waves the ship was enduring were over 110 feet high.[/li][/ul]
Edit, and though not the same as a wind wave, the gigantic landslide-caused waves in Lituya Bay, Alaska, are probably of interest. Washing away trees that are 1600 feet plus above the water is a whole lot of splash.
I’d heard before of the 1958 wave I’ve linked to, but didn’t realize that such waves there are, on a geologic time scale, rather common.
If you do a little digging, a number of other, taller waves have been recorded. Perhaps what is significant about this one is the location and the buoy?
The Alaska earthquake in 1964 generated several tsunamis, one of which was 219 feet. In Lituya Bay, in 1958, a tsunami reached over 1,700 feet (not a rogue wave and thankfully a very confined phenomenon). cite
Hurricane Ivan proved that hurricanes can generate very large waves that are not rogues, but are simply a function of the storm. Ivan went over an array of Naval Research Laboratory equipment in the Gulf of Mexico and revealed that 90 foot waves were common. cite
There’s more out there if you look for it.
TL;DR not sure why this wave is a story. There are well documented cases of bigger waves. Given the right conditions (hurricanes, for example), very big waves appear to be relatively common.
Swells are long wave length and have the sinusoidal shape and travel the ocean.
Seas are caused by local wind and have a more triangular shape… the approaching front is steeper because the water is being pushed along rather then pushed down.
In the storm the seas and swells usually are at different times, but if a sea wave can add to the swell… now you can get multiple swells or multiple sea hit in all the combinations.
A shallow lake could have a wave formed by storm surge… because the storm surge is significant amount of water compared to the depth… the energy of the surge is not going to dissipate into the depths, its going to remain a surface wave.
The article is wrong. It says “Wave height is defined as the distance from the crest of one wave to the trough of the next.”
Ok, that’s true, but the buoy actually measured “significant wave height,” which is different. It’s the average of the highest 1/3 of waves measured by an instrument, usually considered to be about 15-20 waves. So this 62.3 feet record is the average of the tallest 15-20 waves that were passing the buoy at the time. Actual wave heights can be estimated to be from 60-200% of that number, and in fact, the buoy actually recorded one wave that looks to have been about 27 meters: World Meteorological Organization's World Weather & Climate Extremes Archive
EDIT: I’m slightly off in that last sentence. That graph is hourly significant wave heights covering several months. The 27 meter wave doesn’t appear to be on the same date as the record breaker.
I agree with all you’ve said. Although I’d go a bit further than that.
Absent any qualifier, “distance” means in the horizontal direction, not vertical. Also, “trough of the next” is the trough following the crest following the crest they’re referencing.
Far better had they said “Wave height is defined as the [del]distance[/del] *height difference *from the crest of one wave to the following trough [del]of the next[/del].”
It’s not that hard to write a minimally ambiguous sentence. But they have to bother to try. Idjits.
