DC's Fire and EMS Chief John A. Donnelly Sr. said that all search-and-rescue efforts taking place right now are in the water and that conditions are dangerous, reports CNN.
"The challenges are access. The water that we're operating in is about 8 feet deep, there is wind, there is pieces of ice out there so it's just dangerous and hard to work in," Donnelly said.
"The water is dark, it is murky, and that is a very tough condition for them to dive in."
He added that recovery efforts will likely take several days.
"If you can imagine, the river is a large black spot at night with no lights on it, except for a few buoy lights," he said.
Donnelly said he expected the investigation into the collision to take longer.