Friday became the wettest day in Seattle in the past 10 years, and the most rain recorded for Dec. 20 since record-keeping at Seattle-Tacoma International Airport began in 1945. The National Weather Service said the airport recorded 3.25 inches (8.25 centimeters) of rain Friday, making it also the fifth rainiest day in city history.
Seattle also broke a daily rainfall record on Thursday with 2.91 inches (7.39 centimeters) of precipitation, making it the 11th wettest day recorded at the airport. Parts of the soaked Seattle region and western Washington are under a flood watch through Sunday evening. Rivers in King and Snohomish counties are expected to crest and slowly recede Saturday. The weather service warned drivers not to go through flooded areas as that “is the cause of most flood related deaths in Washington.”
The low-lying areas of the northern Oregon coast are also at risk for flooding. Astoria saw 3.42 inches (8.69 centimeters) of rain on Friday, breaking a record previously set 113 years ago. There also remains an increased threat for landslides in western Washington with high levels of soil moisture expected through the weekend. Multiple mudslides were reported Friday.
Snow is also falling in areas above 3,000 feet (914 meters) in elevation. The weather service issued a back country avalanche warning for the Mount Baker area for Saturday. Friday also broke a record for measured sunlight in Seattle. The University of Washington recorded just 0.37 million Joules of solar radiation, the lowest level of sun energy measured since the university started counting over the past 20 years.