Nearly 80 people have been rescued, and two people confirmed dead, after flood hit national park

A US border patrol technical search team is expected to deploy in the Grand Canyon, as authorities continue the search for at least one missing person after a fatal flash flood washed through the national park over the weekend.

Authorities are rushing to scour the area as more heavy rain and thunderstorms in weather forecasts threaten additional debris flows, flash floods or rock falls.

Officials say one person still unaccounted for as forecast heavy rain and thunderstorms threaten further flooding

A second death was confirmed by National Park Service officials on Monday after a flash flood sent a surge of water and debris through an area of the Grand Canyon over the weekend.

Dozens of visitors had to be evacuated by helicopter during the deluge, which consumed trails and infrastructure. Nearly 80 people were rescued and one person is still unaccounted for, as more heavy rain and thunderstorms in the forecasts threaten additional debris flows, flash floods or rock falls, the NPS said in a statement.