Answer:
The word in the sentence which functions as an objective complement is the following one:
dangerous.
Explanation:
Check it out:
The meteorologist  considered  the impending storm  dangerous.
     ↓                ↓             ↓               ↓
  subject           verb      direct object   objective complement
If we ask the question: "What did the metereologist consider?", the answer is: "the impending storm", which is the direct object.
If the question is: "What did the metereologist consider the impending storm to be like?", the answer we get is: "dangerous", which appears right after the direct object and refers to it. In other words, it complements it.
