Check with your local ARES organization, or perhaps the red cross. They might tell you. MARS is not allowed to publish the frequencies they use to the general public, although they're not that hard to find on the air. I suspect other federal agencies have the same rules.
Most of the activity will be 2m VHF and those frequencies vary widely depending on the region. Some of it will be repeaters if available and some will be simplex FM.
The HF activity will come into play in more major disasters with widespread issues.
new jersey 
Linear Mode
