Hawaiian Volcano Observatory issues “Red” aviation warning relating to Kīlauea

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."

> "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"

[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."

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

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

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

See also Yellowstone

> 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

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.

> 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...

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

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.

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?

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.

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.

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.

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

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.

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.

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.

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.