[–] lutorm link

Ash output is apparently already declining, so even though the trade winds are expected to slow it appears the NWS just canceled the ash warning: "Cancelled the Ashfall Advisory for Kau District as volcanic ash emissions at Halemaumau have decreased since Tuesday evening. However, vog will be particularly thick today on the Big Island as sea breezes and upslope flow will collect the plume over the island."

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[–] Casseres link

I'm an air traffic controller at HCF Center (the airspace that has this aviation red warning). I wish I was working there right now to see this firsthand, but I'm currently in Oklahoma City at the FAA center. If anyone has any questions, I'll do my best to answer them.

The summary says the ash cloud is drifting southwest which would put it on the south end of the Big Island. Almost no one flies that way so it shouldn't have a big impact on aviation traffic.

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[–] raverbashing link

> "Despite the lack of time, Moody made an announcement to the passengers that has been described as "a masterpiece of understatement":[3]"

> "Ladies and gentlemen, this is your captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them going again. I trust you are not in too much distress"

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[–] RubenSandwich link

That quote is a masterclass in the British stiff upper lip.

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[–] lightbyte link

Seems like that wasn't an understatement, they didn't end up being in any distress at all. The plane landed safely and nobody was injured.

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[–] walrus01 link

A 747 gliding all engines out and not immediately above an airport is kind of a major crisis. The number of times that has happened is an extremely rare occurrence.

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[–] hansthehorse link

On average and handled correctly, a 747 at 40000 feet has about 100 miles of range, discounting winds.

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[–] walrus01 link

Which is not a lot, if the only airports within 100 miles have runways too short for a 747.

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[–] snuxoll link

What about a body of water? It’s not ideal but it seems like the best option if there’s no suitable runway.

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[–] B1FF_PSUVM link

[nutshell from first link:]

"Because the ash cloud was dry, it did not appear on the weather radar, which was designed to detect the moisture in clouds. The cloud sandblasted the windscreen and landing light covers and clogged the engines. As the ash entered the engines, it melted in the combustion chambers and adhered to the inside of the power-plant. As the engine cooled from inactivity, and as the aircraft descended out of the ash cloud, the molten ash solidified and enough of it broke off for air to again flow smoothly through the engine, allowing a successful restart."

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[–] fhood link

I am amazed that they managed to get the engines on the British Airways flight running again

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[–] huy-nguyen link

They didn’t. The engines started working again once the aircraft clears the volcanic ash cloud.

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[–] walrus01 link
[–] jonknee link

And life goes on, love this angle of ash behind golfers:

https://twitter.com/GettyImagesNews/status/99653888156569191...

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[–] thrav link

My wife and I just got back on Saturday from a visit. Life very much goes on. Throughout the whole week, everyone back home was freaking out / trying to make sure we were alive, while the locals all just kinda shrugged and said, “Just Pele doing her thing.”

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[–] sandworm101 link

I find it hard to take a disaster seriously when people are playing golf. At what point do they start telling the tourists to leave, or at least stop arriving? I'd imagine a mass evacuation of Hawaii, or any part of it, would be a logistical nightmare.

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[–] jcranmer link

Hawaii is a big island. Most of the land downwind of Kilauea is a desert in large part due to centuries-long sulfur dioxide emissions as opposed to lack of rain.

Lava is currently erupting in the East Rift Zone of Kilauea. The subdivisions where the lava is fountaining have been placed under a mandatory evacuation, and travel in that region of Kilauea is now limited solely to residents. Places like Hilo and Kailua-Kona are completely unaffected, except maybe for vog and future ashfall issues.

The National Guard for Hawaii is actually presently planning for a potential evacuation of Puna, since lava is currently threatening to close off all of the roads that reach those districts. The restrictions on tourists and vacationers are already in place to facilitate that putative evacuation.

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[–] lutorm link

That's because there is no "disaster". Apart from sucking for the ~thousand residents who are living in the area where the lava is now flowing, there is no effect on the rest of the island.

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[–] maskedSlacker link

This eruption has been going on for 35 years, and there hasn't been a mass evacuation yet. I wouldn't worry about it.

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[–] jonknee link

The island isn't going anywhere, they're not in any danger.

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[–] sandworm101 link

Maybe not today, but the Hawaiian islands are all temporary. There is a reason they get smaller the further they are away from the hotspot. The big island is doomed.

https://hilo.hawaii.edu/~kenhon/GEOL205/Landslides2/default....

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[–] jonknee link

Well on a long enough timeline we're all doomed, but that doesn't mean golf is out of the question. This eruption has been going on for decades (1983!), it's OK to live a normal life on the Big Island.

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[–] jackhack link

In fact, one could say the island is growing.

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[–] privong link

> Hawaii was created by one volcano, while the tectonic plate moved above it. And there's a line of underwater islands all the way to Siberia.

Just a quick clarification: the Hawaiian islands comprise multiple volcanoes. There's at least five that make up the Big Island (Hawai'i): Mauna Kea, Mauna Loa, Kilauea, Kohala, and Hualālai. I think what you mean is that the island chain seems to have been created by a single mantle plume / volcanic hotspot: https://en.wikipedia.org/wiki/Hawaii_hotspot

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[–] jcranmer link

Well, there are two distinct loci of volcanoes at the hotspot: the loci that creates Mauna Loa, Loihi, Hualalai, Lanai, etc., and the loci that creates Mauna Kea, Haleakala, Kohala, Kilauea, etc. It's still referred to as one hotspot, but there may be separate mantle plumes in close proximity.

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[–] privong link

> It's still referred to as one hotspot, but there may be separate mantle plumes in close proximity.

Does it need to be separate plumes or can it be bifurcation of a single plume as it passes through the crust?

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[–] jcranmer link

I don't know the answer to this question myself, and I suspect our knowledge of hotspots is poor enough that no one can answer this question definitively.

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[–] raverbashing link

Thanks for the clarification, and yes, that's what I mean

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[–] sizzzzlerz link

Notice, too, how the chain of sea mounts curves to the east as they near Asia (or, conversely, shifts west as you move away). Some 40 to 80 million years ago, the direction of the Pacific plate shifted 60 degrees although some scientists claim the shift was due to the hot spot moving underneath the plate. Either way, the energy required for that shift boggles the mind.

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[–] dmix link

> And there's a line of underwater islands all the way to Siberia.

Aka the Hawaiian-Emperor seamount chain: https://en.wikipedia.org/wiki/Hawaiian%E2%80%93Emperor_seamo...

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[–] dboreham link

See also Yellowstone

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[–] raverbashing link

Ah volcanoes, the 3d printer of nature.

Some interesting fact I found the other day: Hawaii was created by one (edit) volcanic hotspot, while the tectonic plate moved above it. And there's a line of underwater islands all the way to Siberia.

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[–] sizzzzlerz link

Mauna Kea is on the big island, north of Kilauea. According to the USGS reports, trade winds are currently blowing the ash clouds south-west, away from the summits of Mauna Kea and Mauna Loa. If the winds shift and start blowing north, I would expect that they'd keep the doors on domes closed. If opened, the ash would not only fall onto the scopes, it would get inside the dome, into all the nooks and crannies, and into sensitive equipment. Just having so much particulate matter in the atmosphere would make observing hard anyway so keeping the doors closed seems to be the best solution.

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[–] danielvf link

Just confirming for those that don't know which Hawaiian island is which, Mauna Kea is on the same island as the erupting volcano.

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[–] Johnny555 link

For further clarification, this island is colloquially called "The Big Island", while its official name is "Hawaiʻi" or "Island of Hawaiʻi", which causes further confusion since that's also the state's name (which consists of 8 main islands and many minor islands).

So when news reports refer to "Hawaiʻi", it's hard to be certain what they are talking about without further clarification.

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[–] goodcanadian link

The volcanic ash rarely gets up to that altitude. The reason the telescopes are sited on Mauna Kea is because they are generally above the tropical inversion layer (leading to clear, dry skies). That same inversion layer generally keeps the volcanic emissions down at a lower altitude (not to mention that trade winds generally push the plume in a different direction). When the inversion layer breaks down, there is not much observing anyway as the telescopes are then in the clouds.

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[–] lutorm link

Yeah, just to confirm: the current ash cloud has never gotten higher than 12,000 ft, while the telescopes are at 14,000.

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[–] oceanghost link

Only somewhat related-- you can drive up to the Keck Observatory on Mauna Kea. You need an offroad vehicle, and you have to stop at least once to adjust to the pressure.

I did it once. Driving to an elevation of two miles is terrifying-- and it is cold (I didn't pack a heavy jacket to go to Hawaii), but the view was unbelievable, and it was great to visit the site of so many PBS specials.

The telescope is operated from the University at the base of the mountain so when you arrive there are a reception area and a sort of a cage in the telescope apparatus you can view the telescope from.

I could dig up pictures if anyone is interested but there are more professional ones online I'm sure.

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[–] bumblebritches5 link

What's the altitude in feet? because that sounds a LOT like my trip to Wyoming, I was at either 8400 or 8600 feet, I don't recall which.

It was near the continental divide if that helps.

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[–] lutorm link

The summit is at 14,000ft MSL. It's pretty brutal to go up because unlike when you go to 14,000 ft in e.g. Colorado, here you almost always start from sea level. I always get lightheaded and get a headache every time I go up.

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[–] robohoe link

I've been there last year. The oxygen Level at that height is about 30-40% less so you breathe heavier and you move slowly. It's also utterly cold. Everyone is wearing heavy jackets, gloves, and hats.

It was funny seeing some people drive up in their rental mustangs. I can only imagine their brakes cooking by the base of the mountain after that downhill drive.

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[–] bumblebritches5 link

The oxygen content is mostly the same (i think it's 20% instead of 21%, it's something like that)

What makes it hard to breathe is the reduced pressure.

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[–] sandworm101 link

I suspect they have plans to shut down if the ash swings their way. It probably is a little more complex. If there is significant ash, even just on the ground, then people will track ask into the telescopes. Volcanic ask is nasty stuff in moving parts. Like sandpaper but sharp. I'd consider closing the doors and wait for rain.

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[–] Cthulhu_ link

Isn't that an observatory like I always know them, e.g. with a roof that can close? That.

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[–] crunchlibrarian link

Classic HN, how is the scientific equipment holding up? Dust in nooks and crannies? Why I can't even imagine!

Hmm there are humans on the island as well?

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[–] wlesieutre link

We know what happens to humans in volcanic eruptions, nobody needs to ask about it.

Evacuate the area, wait until it stops, rebuild afterward in the same place because people like Hawaii well enough to accept the risk of living on a volcano.

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[–] Johnny555 link

nobody needs to ask about it

Also any human toll is widely reported in the news media, while effects on scientific equipment is not.

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[–] sgt101 link

In my defence I had assumed that the US authorities will be brilliant at protecting their citizens - especially now that a red warning is out.

The mount kea observatory is a global asset of science - I suspect that it's less important to the US authorities than their people, but it is kinda a global concern.

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[–] sgt101 link

How do the telescopes on Mt Kea protect themselves from the ash? I know that they are on another island some distance from this volcano (I visited a decade or so ago) but does the ash cloud risk transporting damaging particulates to the special glass?

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[–] Casseres link

It's a common report from pilots when we solicit the weather from them. (Every hour when certain conditions are met, air traffic controllers have to solicit PIREPS - Pilot Reports). It reduces visibility similar to haze.

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[–] drak0n1c link

Growing up on the Big Island I remember vog as the primary allergen that people chatted about. Just like pollen allergies elsewhere.

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[–] jobu link

First time I've ever seen the term "vog" (volcanic air pollution) https://vog.ivhhn.org/

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[–] jcranmer link

Kilauea has been at Orange for the past several years--the ash clouds that were generated were small, highly localized, and not really a threat to aviation. On April 30, the erupting fissure (Pu'u 'O'o) suddenly had its floor collapse, cutting off the main escape path of lava. At the same time, there was a massive surge in magma underneath the summit, which shortly thereafter shifted down the flank.

The lava lake at the summit is now a crater over 300 meters deep. This means that, in addition to rocks falling into the crater and subsequently being ejected into the air in the form of fine ash, water is also intruding into the column, which raises the distinct possibility of a high pressure steam explosion. The alert level was changed because there is now a persistent, high-level ash cloud that is traveling some distance. It's not on the same scale as Eyjafjallajökull (the volcano that shut down European airspace), but it is big enough to start wrapping around the Hawaiian islands.

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[–] mhandley link

The definitions are here: http://www.wovo.org/aviation-colour-codes.html

Red means either "Eruption is forecast to be imminent with significant emission of ash into the atmosphere likely." or, "Eruption is underway with significant emission of ash into the atmosphere." In this case, the latter.

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[–] goodcanadian link

All flights should always avoid volcanic ash. I don't know exactly what the colour scale means (probably higher particle density or altitude or extent), but any aircraft would be advised to avoid the plume. In this case, it is not currently interfering with usual flight paths, but the bulletin indicates that the wind direction is expected to change, so I would say it means be advised and monitor the situation.

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[–] United857 link

What does "Red" mean exactly here? All flights are grounded/need to avoid this airspace?

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