The last time New Mexico was (by at least one measure) this dry, Billy the Kid was shooting up the state and pueblo crops in the Rio Grande Valley were wilting.
With February more than half-gone, drought conditions are getting worse, not better, and it seems likely 2014 will be the sixth consecutive drier-than-average year on New Mexico’s Rio Grande. You have to go back before we had river measurement gauges, to estimates based on tree ring records, to find the last time we had a losing streak that long.
From 1873 to 1883, the Rio Grande experienced four straight dry years, had a break with an average year, then another six dry years in a row, according to University of Arizona professor Connie Woodhouse. Since that time, we haven’t had six dry years in a row until now.
With drought stretching from Seattle across the western United States and all the way to Baton Rouge, La., the question of “the worst drought since …” has become a popular weather nerd’s parlor game. How you answer the question depends on where you are and how you want to quantify “drought” there.
In central New Mexico, flow on the Rio Grande is one of the best indicators. It is the sum of the winter snows that fall in the mountains and provide vital water to valley dwellers – plant, animal and human. By that measure, our current drought is a doozy. As measured by natural flows at the Otowi gauge, the point where the Rio Grande passes San Ildefonso Pueblo in north-central New Mexico, just two years since 2000 – 2005 and 2008 – have been wetter than the long-term average. By this measure – multiyear duration of low flows on the Rio Grande – we haven’t had a drought this bad in 130 years.
New Mexico was a very different place in the 1870s and ’80s. We lacked dams to save water during wet years to buffer us during the dry, or the massive groundwater pumps that can draw on our aquifers to water farms and cities when the rivers fail us. We lacked the infrastructure to import large volumes of food when crops here failed.
But if you look at the data, there also are striking similarities.
It’s not just the dumb luck of randomly sprinkled dry years. Tree ring-based studies of Rio Grande flow done by Woodhouse and her colleagues show drought setting in around 1870. Why was it so dry back then? Climate scientists point to a large pool of unusually cool water in the northern Pacific Ocean that can linger for decades, putting a damper on the storm track that brings the Southwest its winter storms. It’s happening now, and it happened back in the 1870s and ’80s. In 1884, the ocean temperature rose and the flows on the Rio Grande began rising. Some scientists also point to a similar pattern in the Atlantic, which can be a drought double whammy when the two phenomena line up wrong.
To a greater or lesser degree, such ocean temperature alignments were behind the famous Dust Bowl of the 1930s and New Mexico’s fierce drought of the 1950s. And they are behind the drought we are in today.
These two-pronged patterns – the “Pacific Decadal Oscillation” and the “Atlantic Multidecadal Oscillation” – explain why droughts here can linger for decades, rather than just being one or two dry years.
In a round of calls to climate experts and historians last week, I could find no direct evidence that drought drove New Mexico’s impish homicidal maniac William Henry McCarty, aka William H. Bonney, aka Billy the Kid. But it’s clear that climate patterns, and drought, were driving the ebb and flow of cattle across the landscape and the growing conflicts that accompanied the movement.
In 1881, the year Pat Garrett shot Billy the Kid, drought reached from northern Mexico across the entire West, from California through New Mexico to Texas and north into the Great Plains. Historians have suggested drought in the 1870s was one factor behind the spread of Texas cattle into New Mexico. From 1870 to ’77, the years leading up to the famed Lincoln County War, which entangled Billy the Kid and Pat Garrett, Texas was especially hit hard by drought, according to work by Richard Seager, a climate researcher at Columbia University’s Lamont-Doherty Earth Observatory.
In his sweeping Environmental History of the Middle Rio Grande Basin, Dan Scurlock tallied crop losses among Rio Grande pueblos from 1877 to 1893, repeated river drying and sheep losses among the region’s Navajo communities, leading to “raids on Zuni and Hispanic livestock.”
In 1879, one of the worst years, hay crops failed, leaving farmers unable to keep the terms of their contracts to supply the U.S. Army. Even miners suffered because of the lack of water.
“Bad things happen when we have these long-term droughts,” said University of New Mexico climate researcher David Gutzler.