Final answer:
Barbara Bryan's method of knowing about the tornado is unspecified, but plans on how to respond vary between doing nothing and taking shelter or boarding up windows. Tornadoes have significant destructive power, with winds potentially exceeding 500 km/h. Atmospheric pressure changes can indicate the potential for tornado formation.
Step-by-step explanation:
The manner in which Barbara Bryan knew there was a tornado headed her way is not specified in the context provided. However, in general, people might learn of an approaching tornado through various means. Plan A, which involves doing nothing, could potentially result in no cost if the tornado doesn't hit, but could be catastrophic if it does. Conversely, Plan B, taking precautionary measures such as boarding up windows and seeking shelter, might incur costs and effort but could significantly mitigate the damages and risks associated with a tornado strike.
Also, those tornadoes have extraordinary destructive power, capable of blowing houses away and piercing objects with debris. Storm reports often indicate changes in atmospheric pressure, which, when significant, can lead to the formation of tornadoes, producing winds that can exceed 500 km/h. These details underscore the importance of being prepared for such events and making informed decisions based on available warnings and signs of a tornado.