Louisiana residents are experiencing a most interesting time in history. We are having both flood AND drought at the same time. While the Mississippi River reaches flood levels not seen since 1973, the State of Louisiana is also experiencing drought. With the Morganza and Bonnet Carre’ floodways flowing like raging torrents to remove water from the Mississippi River channel, the neighboring landscape is parched, which is wreaking havoc in the agricultural community, fire dangers across the State are high, and lawns and gardens are wilting under the stress of a lack of moisture.
Interestingly, these two events are interrelated, and are likely associated with a phenomenon called La Niña. La Niña is an event that takes place in the tropical Pacific Ocean when the sea surface temperatures become colder than normal. When this occurs, it disrupts weather patterns across the globe, and we have been in La Niña conditions since early winter. Since this past December, conditions were cold in the eastern United States, and snowfall was well above normal across the Great Plains and American Midwest. As such, the snowpack was great and well-preserved deep into the 2011 spring season. As the snow began to melt, it increased river levels on the Mississippi and Ohio Rivers. Relatively high Mississippi levels at this time of year are typical, but not nearly to this extent. This river flow was then exacerbated with heavy spring rainfall, especially in the Ohio River Valley. As storms tracked across the Central portion of the United States – many producing deadly tornadoes – they bypassed Louisiana leaving it high and dry, thereby producing our drought. However, all of the rainfall in the Midwest, compounded by the large volume of snowmelt, is now arriving in drought-stricken Louisiana, and is therefore producing dramatic flooding across our State. So it is therefore possible to have both flood and drought conditions at the same time and at the same place, because the flood waters originated from a different place than the rainfall that would impact drought conditions here in Louisiana.