Tornadoes strike in many areas of the world, but nowhere are they as frequent or as devastating as in the United States. A vast "tornado belt" embraces large portions of the Great Plains of the United States and the southeastern portion of the country. Tornadoes pose the greatest threats to these areas, which are especially vulnerable to abrupt changes in weather conditions.

The word abrupt in the passage is closest in meaning to

• sudden
• vivid
• sharp
• direct