The term POWERFUL BLOW can be summarized by two crossword solutions: SWAT (4 letters) and GALE (4 letters). SWAT stands for Special Weapons and Tactics, a law enforcement unit that is trained to respond to high-risk situations such as hostage taking, barricaded suspects, and terrorist incidents. GALE is a strong wind, usually associated with storms and other extreme weather conditions. Both SWAT and GALE are powerful forces that can cause significant damage.