5/15/12 Volcanoes Disturbing Hurricanes?

With the start of Eastern Pacific hurricane season tomorrow, and Atlantic hurricane season beginning June 1st, the National Hurricane Center is already off to a quick start with a new storm brewing in the Pacific that may become Tropical Storm Aletta in the next 24 hours.

One thing scientists are noticing is that when there is a volcanic eruption like that of El Chichón in Mexico in 1982, and Mt. Pinatubo in the Philippines in 1991, the following years had both hurricane frequency and intensity levels cut in half. With all the gases and particles that the volcanoes release into the atmosphere. Those gases and particles both reflect some light and also absorb radiation, which essentially prevents the Earth's surface from warming as much as it normally would. For example, in the year following Mt. Pinatubo's eruption, global temperatures were about 1°F (0.5°C) cooler, compared with the few years prior. Not only do the volcanoes affect surface temperatures, but also temperatures in the higher levels of the atmosphere as well. By absorbing the radiation given off by the eruption, the developmental stages of hurricanes are affected because volcanic aerosols warm the stratosphere as well.

So how does that affect hurricanes? Hurricanes form by taking the warm temperatures on the ocean surface and lifting it into the cooler layers of the atmosphere. However, if the surface temperatures have cooled, and the upper atmosphere has warmed thanks to the discharged volcanic particles/gases, then hurricane formation will likely never get initiated.

So does this mean we hope for an eruption to kill off hurricane chances? Not entirely. Just because the volcano may hinder hurricane development, doesn't mean it will prevent any storms from forming altogether.

"If there were a very strong volcanic eruption, it is possible the storm season to follow may be repressed," said Robert Korty, an atmospheric scientist at Texas A&M University. "Of course, even seasons that produce few storms can still be dangerous." For example, he went on to explain how overall the 1992 Atlantic hurricane season was an unusually quiet one with only six significant hurricanes. However, one of these was Hurricane Andrew, which prior to Hurricane Katrina, was the most destructive storm in U.S. history.

Sources: Mother Nature Network, National Hurricane Center, Our Amazing Planet, NOAA