(CNN) -- An Alaska Army National Guard helicopter trying to rescue people on Knik Glacier tipped over Tuesday after an icy landing, a Guard spokesman said.
The three crew members of the UH-60 Black Hawk were not injured, said Maj. Guy Hayes, spokesman for the Guard. Winds reaching 70 miles per hour, rain and overcast skies made the mission difficult.
Crews must now reach the three crew members and nine others the helicopter was trying to rescue.
The incident started Sunday when five sightseers became stranded on the glacier after their plane apparently crashed.
Four rescuers reached them with tents and survival gear Monday, Hayes said.
Two Black Hawks attempted the rescue of the nine on Tuesday. The one that tipped over managed to land, Hayes said.
Another helicopter and a C-130 were moving in to reach the 12 people, Hayes said.
Knik Glacier is about 40 miles northeast of Anchorage
CNN's Phil Gast contributed to this article.