Nov 15, 2017

Flood Runoff in Relation to Water Vapor Transport by Atmospheric Rivers Over the Western United States, 1949–2015

Christopher P. Konrad, Michael D. Dettinger
Geophysical Research Letters
  • States that atmospheric rivers (ARs) have a significant role in generating floods across the western United States
  • Analyses daily streamflow for water years 1949 to 2015 from 5,477 gages in relation to water vapor transport by ARs using a 6 h chronology resolved to 2.5° latitude and longitude
  • Finds that the probability that an AR will generate 50 mm/d of runoff in a river on the Pacific Coast increases from 12% when daily mean water vapor transport, DVT, is greater than 300 kg m−1 s−1 to 54% when DVT > 600 kg m−1 s−1
  • Finds that extreme runoff, represented by the 99th quantile of daily values, doubles from 80 mm/d at DVT = 300 kg m−1 s−1 to 160 mm/d at DVT = 500 kg m−1 s−1
  • Concludes that forecasts and predictions of water vapor transport by atmospheric rivers can support flood risk assessment and estimates of future flood frequencies and magnitude in the western United States