Our Evolving Understanding of Extreme Hydrological Cycle Related Natural Hazards and Proactive Mitigation and Adaptation

Natural hazards often occur as a consequence of unusual anomalies in the hydrological cycle. In this talk, I will first provide a perspective on extreme precipitation events as the climate warms, using CMIP5 simulations and reanalysis atmospheric fields. The challenges for quantitative precipitation forecasting (QPF) will also be examined, especially for mountainous regions. Many seemingly disparate forms of natural hazards are intrinsically interconnected and can be simulated with a shared framework. The scalable extensible geofluid modeling for environmental issues (SEGMENT) is such a numerical modeling system, having been applied extensively to polar ice sheets, landslides, debris flows, flash floods and even tectonic earthquakes. In this presentation, I will present two examples to illustrate this point (of modeling philosophy). The first example is the January 8, 2018 mudslides that caused significant losses of life and properties in Montecito, CA. In addition to the unique mechanisms revealed by SEGMENT-Landslide, I will also emphasize the accuracy of QPF in WRF for its accurate simulation. The second example is a major Andes earthquake. The fatigue of the Andes subduction zone, the interface between the Nazca plate and the overlain South American plate, is examined relative to ENSO cycles. Prediction of future major earthquakes (i.e., Mw 5 and above) occurrence (location and timing) will be presented. Mitigation and adaptation strategies in the big data era will be discussed including, possible pathways to communicate such modeling information to relevant community-based decision-making agencies.