Floods and Drought in America
So when it comes to the very critical element of "life sustaining" water, there is also a balance. Every living plant and animal needs water in its cells to survive. Rain falls on the earth and it turns green. The hydrologic cycle promotes life. But too much rain is a bad thing, leading to flooding which can inflict considerable damage to the land, its structures and potentially the lives that occupy that land. On the other hand, too little rain from the heavens will also yield negative results with damage of another kind. Plants and animals might perish after a slow prelude to the inevitable. There needs to be a balance of rainfall/snowfall that equates to each climate zone across the nation. Some areas of the country get rain every month, with some monthsseeing more rain than others. In the western US, the wet and dry seasons are well defined. Some parts of California get no rainfall in the summer, and often go 3-4 months without a drop of rain. That is normal for that region. In other parts of the county it would be catastrophic. In fact, deviations in either direction, wetter/drier, can prove problematic. Too much rain might lead to fungus, mildew or blight on crops- in addition to the flood threat.
When defining a climate, as Koppen has successfully done, the texture of a climate zone isn't necessarily seen as average temperatures and precipitation values- but rather can be best appreciated by the flora and fauna that live there. Look at the trees and flowers, the wildlife that resides in a region. Those elements themselves have been defined by the objective numbers of rain and heat. They are readily apparent. But flora and fauna will also be negatively affected when rainfall numbers vary too far.
Over the past decade, there have been a number of serious droughts in the United States- most recently the deepening drought over much of the nation's mid-section. Only last year Texas and a large swath of the southeastern US was dealing with historically dry weather that affected physiology, agriculture and the economy (especially with those high electric bills). But oddly enough, the same region now undergoing extreme drought in the high plains was enduring widespread flooding only a year ago. And in the wake of former Hurricane Isaac, the Ozarks and areas of the middle Mississippi and Ohio valleys are seeing a reversal of the hydrologic pendulum. Often, similar droughts of the past have been punctuated by tropical storm activity, mitigated and reversed.
The hottest and driest epoch in America, since records have been kept, occurred in the mid 1930s at a time citizens were struggling to stay fiscallyalive during the Great Depression. Another widespread drought dealt a blow from 1987 through 1989 in the "breadbasket" of the country, that was shortly followed by a mild recession. Since the economic meltdown of 2008 we've endured drought and excessively hot temperatures across much of the nation. There almost seems to be a weak correlation of downturns in overall rainfall and the downturns in the economy. This year has been brutal in Texas, Oklahoma, Kansas and up through Missouri to the Chicago area. Not only did it hit 115 degrees in Hill City, Kansas in June with multiple days of 112 degree high temperatures in Oklahoma City and Tulsa, but more than 3,000 record highs were reported only a few months earlier in March from the Dakotas to the mid-west. Mitchell, SD hit 88 degrees on March 18th this year, still officially winter.
When macro scale geophysical entities arise, like an El Nino event or the Madden-Julian Oscillation, these episodes regionally enhance rainfall beyond climatological means. Societies become susceptible to great suffering. Here are someilluminating statistics: Flooding of some type represents 40% of all natural disasters in the world; Flash flooding is the primary cause of weather related deaths; Half of all flood related drowning involve vehicles. 61% of all flood related fatalities in 2011 were male and 39% female. The most vulnerable age group was 50-59.
Considerable advances have been made in the scientific discipline of hydrology, regarding our understanding of how the earth resolves excess rainfall. Specialists are more adept at forecasting river levels and potential flash flooding, given new guidance tools. These tools are borne of improved physical modeling together with better monitoring and observational equipment. Hydrologists have warned the populace to get out of harm's way, through sophisticated computations that predict flood stages. This is also applicable during tropical storm season along America's coastline with improved storm surge forecasts.
Every summer and early autumn across the western United States, wild land fires break out- either naturally through dry lightning strikes or due to human error (or arson). An annual toll is taken on range lands, forests and sometimes structures- affecting people's lives. Fire weather forecasters have full time jobs predicting when and where these events will take place. An entire sub-discipline has been developed for combating wildfires- complete with atmospheric indices that define critical situations and computer models that forecast the indices days ahead. Not only are there specially trainedfirefighters to combat these conflagrations, but air assault teams have been part of the attack for decades. And when large fires burn away trees and ground cover, this greatly increases the likelihood of flooding and mudslides when rain finally returns. It is all part of a symbiosis between dry and wet which makes up the world around us.
Certainly, meteorology is the complicated science of things made of water molecules that fall out of the sky. Meteorologists understand global movement of wind around the world, cold fronts, tropical cyclones, and other aspects of geoscience. But extremes of rainfall or lack of rain cause the most harm to our regional biomes. It boils down to managing the proper dose of rainfall for the earth and its inhabitants to utilize. It is the story of floods and drought in America, a story that is perpetual.
Americans will always live with these extremes. For everything there is a season,
and we enjoy good times while having to cope through bad times. Thestate of our atmosphere is a metaphor of life itself. Dedicated meteorologistshelp the residents of this great nation navigate variabilities of weather. There is no "Perfectville", where such ebbs and flow of weather never happen.And as a meteorologist, I accept the challenge of understanding those variabilities and am eager to do my part and help the people we serve avoidloss of life and property. It is a solemn commission I and others willingly take.