An outbreak of Norovirus among guests and employees occurred at the Seattle Yacht Club. The first known illnesses occurred following a birthday party held on February 25. The guest of honor was among 40 of the 60 people at the party, mostly elderly, who came down with the virus. Members who attended the JO Ball on February 26 also became sick. The club scrubbed the facility clean and reopened, but more people became ill due to exposures on March 5 and 6 so the club closed again for cleaning on March 9.