Hurricanes generally are rated according to the highest sustained wind speed measured using a dropsonde. Tornadoes, in contrast, are rated according to the damage that they cause, not by direct wind measurements. What are some of the disadvantages of rating according to damage? Can you think of a situation in which this would lead to an underestimate of tornado strength?

One of the mainly disadvantages of this form of rating, is that they are talking or measuring based on assumptions not science.

Explanation:

Therefore they don't have certainty and if the primary damage from the Tornado is not big, this one could grow and cause major disasters and put people's life in danger, because the main objective of the measurement is to prevent the population.

For example:

Let's imagine there's a Tornado that is really small and hasn't damage anything yet and it's getting close to the town, let's say Mississippi, and it's going to arrive there in 10 minutes but because it hasn't cause damage the autorities decide that they're not going to ask the population to protect but by the time it hits town, the Tornado grew three times it's inicial size because of the wind so houses are destroyed, nature and lives lost because they didn't have the chance to prevent and protect themselves.