A Year of “Extreme” (Duration) Disasters

This year has been interesting in a number of ways from a meteorological standpoint. It’s been tragic from a human standpoint…and it’s been extreme. And I’m not talking about what you may think. The disasters of 2011 have been, for the most part, either extremely quick to occur…or painfully slow. Tornadoes? Almost instantaneous. But drought and river flooding? Slow enough to the point where a lot of meteorologists call them “boring.”

Hydrograph/Forecast of river levels on the Missouri at Williston: http://water.weather.gov/ahps2/hydrograph.php?wfo=bis&gage=wltn8&view=1,1,1,1,1,1,1,1%22

We’ve had the flood on the Mississippi already. But in progress at present is another extreme flood, this time on the Missouri River. To the left is the hydrograph and forecast from the Missouri at Williston, ND…already at a record level and only forecasted to rise further. This winter has been a perfect storm for this sort of setup. With one of the strongest La Ninas in recent memory in the Equatorial Pacific Ocean, snowpack was high in the Upper Midwest (not unusual). The melt of that, combined with a period of extreme rains from March and April’s severe weather helped push the Mississippi to record levels. La Ninas also traditionally hammer the Northwest US with heavy snowfall. This year was a late bloomer, but when it hit, it didn’t stop from late February through mid to late May. That melt in the Northern Rockies is helping to fuel this record flooding scenario. The meteorological factors coming together this past winter/spring have really not happened since the 70s and possibly not to this level since the 30s or 20s…so it’s not a huge surprise that years from those decades are the years a lot of these records were set.

Speaking of the 30s…similar factors seen in the Dust Bowl era seem to be helping to fuel the epic drought in the Southern US this year.

US Drought Monitor's Map of Texas from Today

The map to the right shows the drought in Texas. The D4 (exceptional drought) area from the US Drought Monitor is currently in place across an uncanny 57.83% of Texas. These are tremendously high numbers that will likely only continue to get worse unless a tropical system impacts the entire state (because I don’t think daily isolated thunderstorm activity is going to really help this). D4 areas are also present across Louisiana, Oklahoma, Georgia, Florida, and New Mexico. With that La Nina, while northern parts of the country bask in precip and snow, the South usually ends up dry. Western Arizona into Southern California were a notable exception this year, but from Eastern Arizona (where the tremendous wildfires are currently burning) through West Texas, the La Nina helped to serve up dry misery.

These events are certainly troubling and certainly tough to swallow, especially if you live in those areas. But they are really far from unusual. They have happened in the past and will likely happen again in the future. The law of averages in weather:

Normal = ((Negative Extremes + Positive Extremes) / Number of Events)

There is no such thing as “normal” weather. While droughts and floods may be slow moving and “boring” though, they are costly, miserable disasters.

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