Storms, floods and atmospheric rivers—Putting the extreme into West Coast extremes

As part of UVic's IdeaFest, the Pacific Institute for Climate Solutions and the Pacific Climate Impacts Consortium invite you to a talk on atmospheric rivers, covering both the current scientific understanding of how they occur and the roles that they play in affecting weather, delivered by Dr. F. Martin Ralph. 

Abstract: Atmospheric rivers (ARs) are narrow, transient corridors of strong water-vapor transport in midlatitude winter storms, corridors of intense winds and moist air centered around a km above sea level and roughly 400-500 km across but thousands of km long. First recognized in about 1998, ARs are increasingly understood to play crucial roles in flooding and water resources along the West Coast of North America (and along west coasts worldwide). ARs routinely transport water vapor at rates equivalent to 7-15 times the average daily discharge of the Mississippi River, and the half dozen or so ARs per year that make landfall on the US West Coast contribute an average of one third to one half of all precipitation in the Pacific coast states, thereby supplying a significant part of their water resources. Notably, ARs also played crucial roles in the endings of almost 80% of extended floods in the Pacific Northwest. Meanwhile, AR storms have been the sources of many (and in some rivers, most) historical floods in the region and are a key driver of potentially catastrophic future flooding as revealed through a USGS-led emergency preparedness scenario for California that quantified "Hurricane-Katrina-like" impacts to California. The discovery of the importance of atmospheric rivers has led to the NOAA-led creation of a new type of weather observing system in California including 100 field sites..  This network has been used to develop a vision for new observations across the entire Western U.S., and major elements of this are applicable to western Canada.

 Biography: Dr. F. Martin Ralph is a research meteorologist who has studied mesoscale and synoptic scale weather phenomena and how they are affected by climate variability. A key area of interest is exploring how to best observe the atmosphere, with an emphasis on advancing the physical understanding of extreme precipitation processes as well as related hydrometeorological predictions and climate projections. He is currently Chief of the Water Cycle Branch at NOAA's Earth System Research Laboratory/Physical Sciences Division, and a Research Associate at Scripps Institution of Oceanography. Dr. Ralph has published over 60 peer-reviewed scientific articles, 23 as the lead author. He has helped lead the establishment of testbeds as a method to accelerate the development and infusion of new science and technology into weather and climate forecasting operations. He has developed new projects, experiments and teams on several subjects, most having to do with observations, physical understanding, and precipitation.

Dr. Ralph will be speaking in place of Dr. Michael Dettinger from the U.S. Geological Survey and Scripps Istitution of Oceanography.