The "Vanuatu Monster" storm

From CNN

From Wiki

First of all, where is and what is Vanuatu? It's an island nation of volcanic origin in the South Pacific some 1000 miles east of northern Australia. If you subscribe to the USGS earthquake notification system, you'll see a lot of alerts about earthquakes near Vanuatu. 65 of Vanuatu's 82 islands are inhabited. The islands are steep, prone to landslides and slippages, and there is little permanent fresh water. The shorelines are rocky and drop quickly into oceanic depths because there is no continental shelf. The active volcanoes are Lopevi and Mount Yasur, with eruptions (undersea) recorded in 2008, and another in 1945. About 267,000 people inhabit the islands. Many people live on less than $1/day, and the infrastructure is weak.

Four cyclones at once

Although two cyclones in the same basin at the same time is not uncommon in the Atlantic or Pacific, four storms at once is rather rare. There are currently four simultaneously in the southern Pacific: Olwyn, Nathan, Bavi and Pam. There have only been four simultaneous hurricanes at once in the Atlantic two times, in 1893 and 1998.* The 1893 hurricane claimed between 1000-2000 lives in Georgia and South Carolina.

Pam, at category 5, is the strongest storm to make landfall since Haiyan hit the Philippines in 2013. Pam has already hit Port Vila, the capital of Vanuatu, a city of 44,000 people. It is likely to hit southern Vanuatu islands early Saturday morning local time. Pam has sustained winds of 165 mph, but as of the time of this writing (Friday, 1:00 PDT which I think is Saturday at 1:00 a.m. in Vanuatu) the reported gusts have been 60 mph. Storm surge and "very rough to phenomenal seas" are expected to affect particularly the central and southern islands.

It's a bit difficult to know what to believe about barometric pressures, as there are no reconnaissance aircraft in the vicinity. Pressures in the eye have been reported to be as low as 870-890 mbar's. If true, the 890 mb is lower than all known hurricanes except Wilma in 2005 (882 mbar's) and Gilbert in 1988 (888 mbar's).  The lowest pressure ever recorded was Super Typhoon Tip (870 mbar's) in 1979.

Why four at once?* There is a wet/dry cycle of 30-60 days known as the Madden-Julian Oscillation, a wave of atmospheric energy that moves east near the equator over these time scales. In one phase, upward motion in the atmosphere is strong, a condition that boosts the formation of thunderstorms. This is the condition now in the western Pacific.This, combined with a strong burst of westerly near-surface winds just south of the equator in the same region this week gave a "boost" to any low-pressure systems trying to get fired up. The result: four storms. See the reference at *, and links within it, for more discussion.

My prayers and thoughts are with the people of Vanuatu as you recover from this storm.

* Discussion from http://www.weather.com/storms/typhoon/news/four-tropical-cyclones-pacific-australia

How does Super Typhoon Haiyan ("Yolanda") compare with Jupiter's Great Red Spot?

Updated: November 8, 2013

Super Typhoon Haiyan is now being called one of the largest storms ever. For a nice display of images of 13 of the largest storms, see here. Other posts on this blog related to this are: Super Typhoon Usagi in the Philippines just six weeks ago, including a Table of the Categories of hurricane (cyclone) strength; Tropical Storm Phailin and Thailand; and Cyclone Tracy and the Bill and Boyd song "Santa Never Made it to Darwin" (because Cyclone Tracy struck on Christmas Eve and Day, 1974).

Here is a link to Dave Petley's Landslide Blog that has a post today on the landslide potential due to the storm.

End of upate______________________________________

Super Typhoon Haiyan, November 7, 2013, 21:30 UTC
NOAA image

Super Typhoon Haiyan is headed toward the Philippines, due for landfall Friday morning (here's the CNN.com report on it). At the moment its winds of 195 mph with gusts up to 230 mph make it a Category 5 on the hurricane scale [Note: Weather.com put the winds somewhat lower--sustained at 134 mph and gusts to 155 mph]. (For comparison, we had a fairly major wind storm on Whidbey Island a week ago with winds up to 40-60 mph! Took down a lot of tree branches and some trees, caused power outages not only here but on the mainland for 8+ hours. Quite humbling to think of what it's going to be like in the Philippines.) This is the largest storm to date this year; its diameter is about 800 km (500 miles). For comparison with Yolanda, the most intense sustained winds appear to have been in about 190 mph in several typhoons (Typoons Tip, Grace, Vera, Sarah in the Pacific, and Hurricanes Allen and Camille in the Atlantic), so Yolanda is on-course to be close to a record-setter. More than 3800 people have been moved to evacuation centers, most from the central region of the Philippines. As shown on the adjacent map, the typhoon is projected to cross the South China Sea (to the west of the Philippines) and then hit Vietnam and Cambodia. It's speed has been 20-24 mph.

Path of Super Typhoon Yolanda

     The winds and rain from the storm are one thing, but there are other dangers. The island of Bohol in its path was hit by a magnitude 7.1 earthquake just a month ago. 350,000 people were displaced by that quake and are extremely vulnerable. Last December, Super Typhoon Bopha hit the southern Philippines, killing over 1000 people and affecting six million. A quarter million homes were damaged or destroyed. Landslides during storms in the Philippines are a constant danger.

Jupiter Great Red Spot NASA image
In the high resolution version of this image, objects as
small as 600 km (~400 miles) can be seen. Thus
Super Typhoon Haiyan, with a diameter of 500 miles--
would be a tiny dot just barely visible.

     According to the International Business Times, a Philippines government website specifically dedicated to disaster reduction was hacked just as the typhoon approached and, as of yesterday, was still not accessible. The website was supposed to provide Filipinos with real-time information about threats such as cyclones, tsunami, floods, landslides and fires, as well as providing general safety advice on preparation and surviving disasters.
     How do our earth storms compare to the Great Red Spot on Jupiter? This storm was first observed by Cassini in the late 1600's, and scientists believe that it is actually older than that. This is an anticyclonic storm (rotates anticlockwise) with a period of about six Earth days (14 Jupiter days). It's 24,000-40,000 km in EW direction, and 12,000-14,000 NS. It is large enough to contain 2-3 Earth's, so even our biggest storms don't compete! Winds around the edge of the spot reach 432 km/hour (268 mph).
    See the Figure caption to compare Super Typhoon Haiyan with the Great Red Spot!