Historic Boulder Rain in a Climate Context

Sep 16, 2013

For those of you covering the historic CO flooding, here is a graphic to help you tell the story. As of today, Boulder surpassed it's annual rainfall record of 29.95" from 1995 - now at 30.12" and counting. Here are some other staggering Boulder rainfall stats:

  • Five of the past 7 days set daily rainfall records.
  • The 9.08 inches that fell on Sept. 12 was an all-time single-day record, nearly doubling the previous record of 4.80 inches set on July 31, 1919.
  • As of 7 a.m. on Monday, Boulder’s monthly rainfall during September stood at 17.17 inches, all but 0.02 inches of which fell during the past week. The previous all-time monthly record was 9.59 inches in May of 1995.
  • This has been classified as a 1 in 1000 year event.

There have also been many questions raised about the connection with this event and climate change. Here's where the science stands:

  • Climate change has already tilted the odds in favor of extreme precipitation events over broad geographical regions, although the specific ties between long-term global warming and short-term weather and climate variability are complex and event-specific at smaller scales. Click here to read more.
  • Colorado's Front Range lies in the transition zone between the region where rainfall is expected to increase in a warming climate and where it is expected to decrease.
  • However, climate studies show an expected increase in heavy precipitation events nationwide even in areas where rainfall is expected to decrease. The Southwest, for example, is projected to see less rainfall overall but more of it coming in the form of heavy bursts.
  • This is due, in part to the increasing amount of water vapor in the atmosphere due to warming air and ocean temperatures.

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