He told CNN's "Starting Point" Friday, "A lot of people are in shock and don't even realize the magnitude and gravity of just how devastating this was."
Grimm, who recently won election to a second term, said displaced families struggle with accessing credit and collecting resources such as apartment security deposits, required to move into other housing, after the storm devastated Staten Island three weeks ago, and expressed concern the cleanup effort will attract less attention over time and "donations will start to go down."
"For now, a little bit of depression starts to set in. This is where we're really going to need volunteers and support the most. This storm is not over, not even close," he added.
The city announced plans to demolish 200 homes that sustained the worst damage, including many on Staten Island, CNN said.