What are the signs of purple clouds in the sky? I met them in high school.

There will be heavy rain, not as heavy as usual, but very heavy. For example, on June 2, 20 19, 10, 12, before the strongest super typhoon "Hibisi" landed in recent decades, spectacular scenes appeared over some areas such as Kyoto, Japan: under the dense cloud background, the whole sky was dyed bright pink-purple, and the intricate picture seemed to be "in an animated scene. Otherwise, something very bad will happen.