POSTED: 01:30 a.m. HST, May 30, 2011
LAST UPDATED: 02:11 a.m. HST, May 30, 2011
I recently returned from a trip to India, where I got soaked by monsoons; Bangladesh, where I watched thunderstorms turn the landscape eerie shades of yellow; and the Philippines, where I escaped a typhoon by mere hours.
The oppressive wet weather took me by surprise. Had I misjudged the timing of seasonal storms in the area? Or was this another case of weird weather caused by global warming, El Nino currents or some rascally extraterrestrials?
As usual with the weather, it's hard to say.
Most of us use the term monsoons for the Asian rains that soak us to the skin in seconds. Technically, though, the term means the entire cycle of wet summers and dry winters in that area. The word "monsoon" comes from the Arabic "mausim," meaning "season."
Researchers know that the monsoons of the area are caused by the reversal of Indian Ocean winds. In winter, from October through May, the trades blow from the northeast. As with Hawaii's tradewinds, this direction brings cool, pleasant weather with occasional windward showers.
During Indian Ocean summers, though, from June through September, the winds blow from the southwest. These are the equivalent of our Kona storms, and like those, they bring hot humid air loaded with rain.
What causes these wind reversals is not fully understood. The process involves interactions between ocean currents, temperature fluctuations, the jet stream and the area's geography. Calculating the relationships of these variable global forces is so complicated that monsoon predictions are notoriously difficult.
Still, these early May storms had even the flood-toughened people of that region talking about the weather. Usually the heavy rains don't start in earnest until June.
The heat made some days uncomfortable but I was glad to experience true monsoons. I had no idea that the rain arrived in spectacular thunderstorms. Mornings were hazy, hot and still, but by afternoon black clouds began to billow and boil, blocking the sun and sending rice harvesters running for cover. The storms raced toward us like mischievous jinni, crashing and flashing as they dumped astonishing amounts of water on everything below.
I spent much of my Asia time in Bangladesh, most of which is a river delta formed by the Ganges and Brahmaputra Rivers (and others), originating in the Himalaya Mountains. The huge rivers carry enormous amounts of sediment that eventually wash into the Bay of Bengal, creating the famous fringed estuary known as the Sunderbans.
The people of Bangladesh and surrounding countries depend on the monsoons to water their endless rice paddies. Often, though, the rain is too much of a good thing and floods destroy fields and villages.
As if frequent flooding from rain isn't enough challenge, Southeast Asian residents must also cope with summer cyclones. During my overnight transit through Manila, newspapers warned that Cyclone Songda was heading toward Luzon. I boarded the plane and got out of there ahead of it. When I stepped off that plane 10 hours later to be greeted by Hawaii's cool, flower-scented tradewinds, I nearly kissed the ground.
In 1999, the Hubble Space Telescope photographed a 1,000-mile-wide cyclone on Mars. Since no one knows why the monsoons and cyclones arrived early this year in Southeast Asia, I'm betting the Martians did it.
Susan Scott can be reached at www.susanscott.net.