When in Doubt about Drought, Turn to the Internet for Answers

Its summer again and its hot and its dry. Although thats pretty normal for here in Oklahoma, a large portion of the country is having one of the driest years on record with drought conditions reported in some regions.

I once had a polite argument with a gentleman from the National Weather Service about what constitutes a drought. At the time it hadnt had rained in nearly two months and I mentioned that I couldnt wait until the drought ended.

"Were not in a drought," he responded.

When I noted the continued absence of rainfall, he acknowledged that it had been a dry summer, but insisted that, "dry does not equal drought."

This summers drought (according to the National Weather Service), already the centurys third worst in the Mid-Atlantic, continued to worsen in mid-August and was spreading into northeastern states, the Carolinas and west into Ohio and Indiana.

The U.S. Geological Survey said that in New England 70 percent of streams had recorded below-normal flows and record lows had been set in 13 percent of those streams. Without fresh water to rinse out rivers and streams, salt water was creeping further up river in many areas, threatening water supplies in Poughkeepsie, N.Y., and in the Philadelphia area.

Curious to find an official NWS definition of drought, I turned to their web site.

At http://www.nws.noaa.gov/om/ drought.htm I found this definition: "A drought is a period of abnormally dry weather which persists long enough to produce a serious hydrologic imbalance (for example crop damage, water supply shortage, etc.) The severity of the drought depends upon the degree of moisture deficiency, the duration and the size of the affected area."

The service cautioned, however, that it was only a general definition. Droughts also can be categorized as meteorological, agricultural, hydrological and socioeconomic droughts.

I thought surely there must be a better definition so I went out searching the Internet and eventually stumbled on the web site of the National Drought Mitigation Center at the University of Nebraska-Lincoln (http://enso.unl.edu/ndmc). Their basic definition stated that a drought was a "a long period of abnormally low rainfall, especially one that adversely affects growing or living conditions."

Along with the four categories of drought mentioned above, the center also has an in-depth discussion about the "operational" and "conceptual" definitions of droughts.

According to the Nevada Division of Water Planning on-line glossary of water terms (http://www.state.nv.us./ cnr/ndwp), there is no universally accepted quantitative definition of drought. "Generally, the term is applied to periods of less than average or normal precipitation over a certain period of time sufficiently prolonged enough to cause a serious hydrological imbalance resulting in biological losses (impact flora and fauna ecosystems) and/or economic losses (affecting man)."

While I was noodling around on the Internet one of those "scattered showers" the weathermen are always talking about moved through my neighborhood. I turned on the Weather Channel and saw the weekend forecast called for a wide area of rain to move through the Mid-Atlantic states and all along the Eastern Seaboard.

At first I thought that the drought was about to end, but I clearly didnt know enough about droughts. After reading a little further, I discovered that, just like a dry spell doesnt spell drought, neither does a passing rain shower mean the end of a drought.