Feb 2018 Southwest Climate Outlook - La Niña Events in the Southwest
Assistant Research Professor, Arizona Institutes for Resilience
Assistant Professor of Anthropology, School of Anthropology
Ben McMahan joined CLIMAS after completing a PhD in Sociocultural Anthropology at the University of Arizona. His dissertation research was on hurricanes and disaster on the U.S. Gulf Coast, where he focused on
- Human interactions in dynamic social and environmental contexts,
- Risk perception and landscape changes during and after disaster, and
- Social network and policy responses to governance issues related to the acute threats of disaster; as they layer onto long term environmental issues and landscape scale changes.
He was also a key contributor to UA Bureau of Applied Research in Anthropology (BARA) collaborative/trans-disciplinary research on the social, economic, and environmental impacts of the US Oil and Gas industry (2007-2011), and the aftermath of the Deepwater Horizon oil spill (2010-2013).
At CLIMAS, his research activities included tracing how climate information is incorporated into regional decision maker networks, leading CLIMAS team research on the risks and effects of climate extremes, and collaborative research on the effects of climate variability on phenology and temporality of native plants in the region. He was also responsible for working to develop collaborative research opportunities and outreach efforts at CLIMAS, and as part of ongoing assessment and science/strategic planning, he contributed to strategic planning used to prioritize future research and outreach directions. He also coordinated publication of the monthly Southwest Climate Outlook, produced the Southwest Climate Podcasts, and was the online editor for CLIMAS’ blog - Southwestern Oscillations.
Winter precipitation (Dec-Feb (DJF)), during most weak La Niña events (ENSO Index Value between -0.5 and -1.0) has been below average, although a few years (1968, 1985) were notable outliers (Figs. 5-6). The monthly breakdown of weak, moderate, and strong La Niña events reveals that while the DJF totals for Tucson, AZ and Las Cruces, NM have been mostly below average (Figs. 7-8), there have been individual months that recorded precipitation above the monthly average (represented by black lines on the plots). The most likely outcome for the Southwest this year is below-average precipitation totals for the winter season, but the way that these events unfold will have an impact on how residents perceive and experience this La Niña event (see the following page for examples from Arizona and New Mexico during La Niña events).
Recent La Niña Events - Winter Temperature & Precipitation (Dec 1 - Feb 14)
Temperature anomalies (show below as departures from normal) have been mostly warmer than average during the core of this winter season (Dec 1-Feb 14) across the Southwest (Fig 9). The accumulation plots in Figure 10 display the average precipitation for this timeframe (blue), the observed precipitation this year (green), and the observed precipitation for two recent La Niña events (red, purple) (Fig. 10). These plots reveal similar accumulation patterns, especially in the southern locations, and highlight just how far behind the normal accumulation we are in most of the Southwest.