Kilauea Volcano on Hawaii’s Big Island has had a reputation of being a gentle giant over the last 20 years, providing guests with glimpses of oozing, slow-moving lava; however, the gentle giant has transformed into an unwieldy beast over the last few weeks, with ash-laden explosions prompting the National Weather Service to issue a new set of weather products. While some sensational headline writers on the US Mainland and Europe have compared Kilauea’s recent activity to the likes of explosive Mount St. Helens or even Krakatoa, the truth is Kilauea and its eruptive activity is still small in the scheme of global volcanoes. But while it is small, it still brings with it many large risks, including that of ashfall.
But unlike the ashes from a cook-out or cigarette or cigar, the ashes that fall from a volcano are nothing more than ground up rock. “It’s really minute particles of rock, ” Hawaii Volcanoes National Park spokesperson Jessica Ferracane told us at the crater rim inside the park on the last day it was open to the public. “This rock is getting pulverized by the gases in it, when it hits the magma, its a chemical reaction that happens, and big chunks of rock can come out, but so can small pulverized particles that come out as volcanic ash.” Each time there’s some instability at the top of the volcano and rock falls into it, the stage is set for a possible ash event.
Halema‘uma‘u, the largest crater in Kīlauea Caldera was the site of more than 50 explosive events during a 2.5-week period in May 1924. The explosions were then, and remain today, the most powerful at Kīlauea since the early 19th century, throwing blocks weighing as much as 14 tons from the crater. Halema‘uma‘u doubled in diameter, deepened to about 1300 feet, and drastically changed in behavior. In an alert issued prior to the national park closing, the USGS says, “The steady lowering of the lava lake in “Overlook crater” within Halemaʻumaʻu at the summit of Kīlauea Volcano has raised the potential for explosive eruptions in the coming weeks. If the lava column drops to the level of groundwater beneath Kīlauea Caldera, influx of water into the conduit could cause steam-driven explosions.” Steam driven explosions could be extremely dangerous; they add, “Debris expelled during such explosions could impact the area surrounding Halemaʻumaʻu and the Kīlauea summit. At this time, we cannot say with certainty that explosive activity will occur, how large the explosions could be, or how long such explosive activity could continue.” The USGS says Hawaii County Civil Defense will issue additional alerts should the explosion become imminent or is underway.
Since then, many explosions have occurred, launching ash high into the air. The highest sent a plume of ash 30,000 feet into the air; the most voluminous one belched out a cloud that could be cast in any apocalyptic movie. Even larger explosions could happen in the coming days and weeks, perhaps impacting commercial aviation in a much larger way than it does today. While there have been some localized ash fall events over the years at Halema’uma’u, that ash fell near the caldera in closed-off areas of the National Park. But with larger explosions and more abundant ash at play, the risk of ash blowing and falling in a much greater area is now here.
With the threat of falling ash, the National Weather Service in Honolulu has created special products to keep the public informed of the risks posed by the ash. NOAA meteorologist John Bravender, who works at the Honolulu office of the National Weather Service, told us how they’ve developed the advisories. “The volcanic ashfall program is something we’ve been working on quite fast over the past week or two. As the weather forecast office, we’ve had responsibility for issuing SIGMET and aviation warnings but given the past history from our volcanoes, haven’t really been really concerned about ashfall. ” Bravender said the team there has had a “crash course” of sorts to develop a program, relying on experts from other groups such as Hawaiian Volcano Observatory (HVO) and the Alaska Aviation Weather Unit. But unlike severe weather watches that are issued ahead of other severe weather events, you won’t see an Ashfall Watch posted. “There’s no watches; these are very reactive products, ” Bravender told us.
When an ashfall incident is imminent due to some type of explosion at the volcano, the National Weather Service office in Honolulu will issue one of three types of products. The first is a Special Weather Statement. A Special Weather Statement is issued when there is the potential for trace amounts of accumulating ash. When there’s a chance of a more significant ashfall, from over a trace to up to 1/4″, the National Weather Service will then issue an Ashfall Advisory. And if a heavy ashfall is expected with accumulations greater than 1/4″, an Ashfall Warning is issued. As of now, only Special Weather Statements and Ashfall Advisories have been issued for the explosive events at Kilauea.
When any of these products are issued, the National Weather Service encourages people to avoid ash. “Avoid excessive exposure to ash which is an eye and respiratory irritant,” the Special Weather Statement text reads. “Those with respiratory sensitivities should take extra precaution to minimize exposure.”
The International Volcanic Health Hazard Network (IVHHN), the Cities and Volcanoes Commission, GNS Science, and the USGS developed guidelines on preparedness before, during, and after an ashfall.
Stock essential items; a sustained ashfall may keep people housebound for hours or even days. Based on the guidelines you should:
- have dust masks and eye protection
- have enough drinking water for at least 72 hours (1 gallon water per person per day)
- have enough non-perishable food for at least 72 hours for family and pets
- get plastic wrap to keep ash out of electronics
- get a battery-operated radio and extra batteries
- have lanterns or flashlights and extra batteries for both
- keep extra stocks of medicine for people and pets
- have a first aid kit
- prepare cleaning supplies, such as a broom, vacuum cleaner with spare bags and filters, and a shovel
- get a small amount of cash; sources such as ATMs and banks may not be open
- consider that you could be stuck in your vehicle, so store emergency supplies in your vehicle too
When a Special Weather Statement, Ashfall Advisory, or Ashfall Warning are issued for your area, take immediate action to protect life and property.
- close all doors and windows
- place damp towels at door thresholds and other draft sources, like window cracks
- protect sensitive electronics and do not uncover until the environment is totally ash free
- disconnect drainpipes and downspouts from gutters to stop drains from clogging, but allowing ash and water to empty from gutters onto the ground
- if you use a water catchment system, disconnect the tank prior to the ashfall
- if you have respiratory illness, such as chronic bronchitis, emphysema, or asthma, stay inside and avoid unnecessary exposure to the ash
- ensure livestock and pets have clean food and water
If volcanic ash is falling, stay safe!
- don’t panic; stay calm
- stay indoors
- if outside, seek shelter such as a car or in a building
- use a mask or cloth over your nose and mouth
- if a warning is given before ashfall starts, go home from work; if at work when ashdall starts, stay indoors until the ash has settled
- do not tie up phone lines with non-emergency calls
- listen to your local radio for information on the eruption and clean-up plans
- do not wear contact lenses as these will result in corneal abrasion
- if there is ash in your water, let it settle and then use the clear water. If there is a lot of ash in the water supply, do not use your dishwasher or washing machine. Water contaminated by ash will usually make drinking water unpalatable before it presents a health risk
- you can eat vegetables/fruit from outside, but wash ash off first
Volcanic ash, even in small quantities, can do harm on the surface. A light coating on car or home windows can scratch them; great care should be used when removing ash. Ash entering water catchment systems can contaminate their contents, clog filters, and/or do harm to pumps. More substantial eruptions can also impact cars and jet aircraft.
The National Weather Service says in the event Kilauea creates a large ash loud, NOAA’s Volcanic Ash Advisory Centers (VAAC) will issue critical guidance to help aircraft steer away from destructive ash particles. NOAA’s VAAC has been providing guidance on remote volcanoes erupting in/around Alaska that could pose an aviation threat too.