Friday, November 14, 2008


We woke up this morning with burning eyes and runny noses to see Hilo Bay completely obscured by the Vog. At swimming, everyone was complaining about feeling lethargic and struggling with their laps. “Vog” is a term used in Hawai‘i to describe the hazy conditions caused by volcanic gases being emitted into the air and mixing with water vapor and very small particles, primarily sulfur compounds and sulfur dioxide. The main sources are from the Halema‘uma‘u and Pu‘u ‘O‘o vents on Kilauea volcano which are spewing white clouds with glowing red embers.

Kilauea volcano is extremely active right now. The toxic volcanic gas emissions increased significantly after the March 19, 2008 Halema’uma’u explosive event and have resulted in parts of
the island being declared a disaster area due to Big Island famers and flower growers losing their crops. Some towns have become almost uninhabitable for people with respiratory problems and the county has notified island residents that they should not wait for an evacuation order if they feel ill from the volcanic output.

Normally, the trade winds blow the Vog south and west towards Guam. Towns in the district of Ka’u have been dealing with the worst of the vog since the onset of the increased activity, but the trade winds blow some of the Vog around behind Mauna Loa which builds up over the western side of the Big Island on the Kona and Kohala coasts as well. When the trade winds are blowing, the wind off the ocean keeps Hilo and most of the eastern side of the island free of Vog.

The trade winds blow 92% of the time during the summer but start to diminish in the winter when trade wind activity is only 40% of the time in January.

Before this last eruption the last major Vog releases were in the early 1980s and they did not last more than 3 weeks. The current intense Vog emissions have been going on for 9 months.
As we head into a quarter with fewer days of trade winds, we are preparing for a season of intense Vog in Hilo. We have noticed on days that Hilo gets high Vog readings; Kona is usually getting some relief. We get our Vog readings from the EPA air quality site. We also monitor the discharge of volcanic gasses by looking at the USGS real time volcano cameras and the current seismic activity on the Big Island on the USGS recent earthquakes site.

We are preparing in advance for Hilo’s Vog season. We have our SO2 detector nearby and our stash of gas masks and our predetermined route out of town if the detector goes off. We have a HEPA air filter to help with headaches and lots of green tea to help our sore throats. We are making a list of things we want to do on the western side of the Big Island since we have been avoiding it since last February due to their Vog problems. Kona has awesome snorkeling and we have been eager to check out some hiking trails in Kohala.

We may be completely wrong on our prediction of Hilo’s Vog Season as we are not Volcanologists. The county has limited resources for dealing with the impact of the volcanic gasses and lava flowing into the ocean and rarely updates their Civil Defense web site. The Hawaiian Volcano Observatory has daily updates, photos and videos of the volcanic activity but does not address the activity or health impacts outside the National park.
So this is just our best guess in the spirit of being proactively prepared while living so close to an erupting volcano.


Anonymous said...

I've never correlated the smell of burning ash to vog days here, but now that you mention it, it smells like sitting down-wind of a big bonfire.

larry said...

you can see how voggy each side of the island is by visiting the two web sites below, they are web cams looking out to sea (scroll to bottom of the page)

and when the trades die down the vog comes to hilo town (mostly from Pu‘u ‘O‘o which back in july 2007 was hardly emitting any gas: then the floor of the crater collapsed and ever since then it's been emitting tons of gas)

as for a vog "season," there is one since there are seasonal changes in wind direction and intensity and until the volcano decides to stop spewing tons of gas there will continue to be vog and it will move with the winds.

BNS said...

Aloha from the Kohala Coast. We have been suffering from heavy vog this past week, too.

You might be interested in this site, which shows a graphic of the SO2 over the islands based on satellite imagery (although sometimes the graphic has gaps).

I'd like to know more about your SO2 monitor. Exactly what kind is it, and where did you get it? If you wouldn't mind telling me, you can email me at therightblue at gmail dot com.

We, too, use HEPA filters, but we still get headaches and coughs, and our poor 12 yr old cat has developed asthma.

Stay well over there. Pray for tradewinds!


Keahi Pelayo said...

It has been bad in Honolulu too.

ContractCentral said...

ftb: "Normally, the trade winds blow the Vog south and east towards Guam."

I'm sure you meant to say "west towards Guam" :)

Great blog btw!