CREDIT: AP Photo/Ted S. Warren
An unseasonable series of storms hit the Pacific Northwest over the weekend and into Monday, dropping record amounts of rainfall, leaving more than 12,000 residents without power, and even causing a rare tornado to touch down near Seattle.
The National Weather Service said the storms were “extraordinary for late September” and “much more like a November storm.”
The storms brought hurricane-force winds and an onslaught of rain that smashed long-held precipitation records in the region. The Oregonian reported downtown Portland recorded 6.21 inches of rainfall from the beginning of the month through Sunday evening, the most in any September since recordkeeping began in 1872. In addition, “Astoria recorded 10.1 inches during the same period, the most since records were started in 1890 and a drastic increase from the city’s ‘climatological normal’ of 2.14 inches for the month of September.”
And in Washington, as of Monday evening, Olympia had recorded more than 9 inches of rain, topping a 1978 record and swamping the usual 1.7 inches that fall in that time, the National Weather Service said. Sea-Tac Airport’s September rainfall total hit 6.16 inches by 6 p.m. Monday, beating a 1978 record of 5.95 inches.
Though the region is no stranger to wet weather, the storms concluded what is now the wettest September on record for multiple cities throughout the region — including Seattle and Olympia, Washington, as well as Portland, Salem and Astoria, Oregon.
According to Climate Central, this unusually intense event was the product of a long plume of moisture aimed directly at the Pacific Northwest. Further, “these moisture plumes are sometimes called ‘atmospheric rivers,’ which are responsible for some of the most damaging flooding events along the U.S. West Coast, particularly in California.”
To make matters worse, a study released earlier this year found that climate change may lead to an increase in atmospheric rivers and their resultant extreme precipitation events. As the climate warms, the atmosphere can carry more water — meaning more intense rainfall and flooding. The head of the research, Dr. David Lavers, from the department of meteorology at the University of Reading, told Climate Central that “the link between ARs and flooding is already well established, so an increase in AR frequency is likely to lead to an increased number of heavy winter rainfall events and floods. More intense ARs are likely to lead to higher rainfall totals, and thus larger flood events.”
Some good news for Americans facing extreme weather in the coming days: National Weather Service will continue forecasting weather and distributing severe weather watches and warnings, despite the government shutdown.