Omigosh. Check this out. Spooky cool!

Labels: clouds, satellite imagery

I had planned to write about vog next week, but NASA's Earth Observatory has forced my hand this morning by publishing this:

What you see in this image of the Hawaiian islands is a lot of vog, an acrid mix of sulfur dioxide, water, and oxygen that results when volcanic emissions mix with the atmosphere.

When I was there last week, I experienced some vog, starting with the source. Here's Halema'uma'u Crater (part of Kilauea Caldera), steaming away in Hawai'i Volcanoes National Park, spewing water vapor, carbon dioxide, sulfur dioxide, and other gaseous goodies upward and downwind:

The prevailing winds keep these nasty gases close to the ground west of the crater, resulting in the park service closing down the roads in that area of the park.

From there, the gases drift west and north, mixing and interacting with the atmosphere, forming vog. If the trade winds aren't active, the vog kind of stalls on the western side of the big island, and even drifts along the archipelago to plague Maui and the other islands.

On Thanksgiving day, I was standing on top of Mauna Kea, one of the five volcanoes that makes up the island, and on the descent back down the mountain, looking south towards Mauna Loa, where I could see a curtain of vog on the western flank of the big mountain (obscuring Kona and the coast):


Now here's a zoomed-in shot, augmented with a dotted line to show you approximately where the silhouette of Mauna Loa would be, if you could see it through all the vog there on the western side of the mountain. Honestly, it looked just like a curtain of greyish white hanging from the sky: palpable and with a discrete edge:


Down in the thick of it:


It wasn't as noxious as I thought to be in it and breathe it, but the vog definitely had a distinct scent and taste, and my eyes were watery (though that may have been psychosomatic, because it was kind of freaky how thick it was).

According to my friend Lily in Waimea, the trade winds have picked up in the past day or so, though, and scrubbed away the vog. So: clear skies return to Hawai'i... but for how long?

Labels: clouds, geology, hawaii, national parks, travel, volcano

One final shot from Northern Ireland: me holding up a cloud. Sunset, December 30, 2007: Port Rush, County Antrim.

Labels: antrim coast, art, clouds, northern ireland

Geological travels in Northern Ireland, part II:

Mammatus clouds hanging over Lough Erne, in western Northern Ireland. Our friends Jodie and Rory have a caravan on this large lake. After our tour of the cathedrals of Armagh, Jodie drove us out here to have a hike at the lake (which was great in spite of ending in darkness and rain) and to rest up in their modish accomodations there.













This is Mount Slemish, an eroded volcanic neck in Northern Ireland near Antrim. This "basalt plug" was once the center of a volcano which erupted lava all over this vicinity. Because the massive basalt in the volcano's "throat" was tougher than the surrounding stratified rock layers, it stood up strongly to erosion, and now rises to 1,457 feet (437 m) in elevation, dominating the local landscape.

Labels: clouds, northern ireland, slemish, volcano