Here, warm air flows up from the Gulf of Mexico in the spring and summer and crashes into cold air pushing down from Canada.The meeting produces violent thunderstorms called supercells.

• 每年春夏两季，暖气流从墨西哥湾北上，遭遇从加拿大南下的冷空气，继而交汇形成破坏性极强的雷暴，超级风胞。