This is how the state of Nevada defines an act of terrorism:
1. "Act of terrorism" means any act that involves the use or attempted use of sabotage, coercion or violence which is intended to:
(A) Cause great bodily harm or death to the general population
(B) Cause substantial destruction, contamination or impairment of:
(1) Any building or infrastructure, communications, transportation, utilities or services; or
(2) Any natural resource or the environment
2. As used in this section, “coercion” does not include an act of civil disobedience.
(Added to NRS by 2003, 2947)
So yes, this is terrorism.