The active typhoon season was also impactful. More storms passed near Hong Kong in 1964 than in any prior year. The Royal Observatory Hong Kong issued tropical cyclone warning signals 42 times for ten different storms; these warnings were in effect for 570 hours. Two of these storms, Ruby and Dot, prompted the highest warning signal, signal no. 10. No year prior to 1964 featured more than two typhoons affecting Hong Kong on record. Ten typhoons impacted the Philippines, including Winnie (known as "Dading" in the Philippines), Luzon's severest typhoon since 1882. The effects of typhoons in 1964 led to a 3.1 percent decrease in rice output from the Philippines. Six typhoons and two tropical storms struck Vietnam, including three tropical cyclones in a twelve-day period in November. The combined effects of Iris and Joan killed as many as 7,000 people and led to the worst floods in six decades.