Yellowstone National Park, which was hit by devastating floods last week, partially reopened Wednesday, with long queues forming at entrances to the US landmark before dawn.
Hundreds of visitors in cars, campers and trucks waited to get into the oldest national park in the United States, where roads and bridges were swept away in the wake of torrential rainfall and rapid snowmelt.
Thousands were urged to leave the park, and dozens of people had to be airlifted to safety after mudslides and rockfall cut roads in the northern section of the park.
The National Park Service, the government body that operates Yellowstone, said last week that sections of the park -- home to the Old Faithful geyser -- would likely remain shuttered for the rest of the year.
On Wednesday, the southern part of the park was open to visitors, whose numbers were being controlled by a license plate system that allows even numbers in on even dates, and odd numbers on odd dates.
"Unprecedented amounts of rainfall caused substantial flooding, rockslides, and mudslides within Yellowstone National Park," the NPS said Wednesday.
"Historic water levels caused severe damage to roads, water and wastewater systems, power lines, and other critical park infrastructure.
"Visitors may now access the south loop of Yellowstone via an Alternating License Plate System. The park's north loop remains closed due to flood damage until further notice."
Yellowstone Park welcomed more than 4.8 million visitors last year.
The park was the inspiration for Jellystone Park, the home of beloved cartoon favorite Yogi Bear -- an affable but permanently hungry character whose chief preoccupation was stealing picnic baskets and outwitting a park ranger.