Tropical Cyclone Pam is continuing to gain strength as it menaces the island nations of Vanuatu and Fiji, packing maximum sustained winds of 155 miles per hour, which is the equivalent of a Category 5 hurricane. A direct hit on Vanuatu, which is a nation comprised of numerous but sparsely populated islands, is possible — though it is not forecasted to occur, according to the U.S. Joint Typhoon Warning Center, which is run by the Air Force and Navy.
Instead, the storm is predicted to lash Vanuatu with heavy rains, high winds and storm surge flooding, potentially even exposing some islands to part of its eye wall, where its most intense winds and rains are found. Parts of Vanuatu, which has a population of about 253,000, are likely to see winds of up to 100 miles per hour even if the storm does not make landfall, with worse impacts if it does come closer to the country.
Fiji is also projected to be affected with winds and rain, although the storm may not make landfall there, either. However, while Fiji will be on the storm’s weaker, western side, Vanuatu will be in the storm’s right, forward flank, where the winds plus the motion of the storm add up to make even stronger wind gusts and a higher storm surge.
Both Vanuatu and Fiji are among the many small island states that have been advocating for the world to undertake stringent and rapid greenhouse gas emissions cuts in order to lessen the effects of global warming. Rising sea levels are already affecting these islands and others, such as the Maldives, with storm systems such as cyclones only adding to the sea level rise impacts through storm surge flooding.
Cyclone Pam is located in an area that has an extraordinary supply of warm, deep ocean waters to help fuel the storm, and a phase of natural variability in the tropics known as the Madden-Julian Oscillation, or MJO, is also favoring tropical cyclone development in this region. The MJO is a tropical disturbance that propagates eastward around the global tropics with a cycle on the order of 30 to 60 days. It influences the precipitation patterns in the tropics, as well as atmospheric circulation and surface temperatures, according to the Climate Prediction Center in Maryland.
Next 2 week forecast of the MJO shows eastward propagation across the Pacific pic.twitter.com/0sY9HA9MEO
— Michael Ventrice (@MJVentrice) March 11, 2015
Just incredible. 4 tropical cyclones, two of which are identical twins about the eq. Doesn’t get prettier than this. pic.twitter.com/83OCSANXoW
— Michael Ventrice (@MJVentrice) March 12, 2015
“Tropical cyclones typically form in any regions where the MJO has recently been (or currently is),” says Adam Sobel, an atmospheric scientist at Columbia University. Based on the phase of the MJO at this point, this favors tropical cyclone development in the South Pacific Ocean near Australia at this point, he told Mashable in an email.
As of Thursday morning eastern time, four cyclones were spinning around the periphery of Australia. None has had devastating impacts to any land areas, at least so far, but Cyclone Pam poses the biggest threat at this point.
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