Despite slippery conditions and a new fee, 11,200 people took in Wisconsin's Lake Superior ice caves over the weekend.

Ice formations around the caves are not as large as they were last year but are especially colorful, said Julie Van Stappen, chief of planning and resource management for Apostle Islands National Lakeshore.

"The ice formations still are really beautiful," Van Stappen said. "The cool thing is that each year it's a little different — it's unique."

Parked cars lined up for more than two miles on either side of the access point on Meyers Beach Road, and about 2,000 people had started the walked across the ice by 11 a.m. on Saturday, the park service said.

The ice is also very slippery. Park officials recommend that visitors wear ice cleats or use ski polls to avoid falling down. They also warn that it's colder on the ice than it is on land.

"This year we haven't had much snow," Van Stappen said. "The walk out there, there's a lot of bare ice — in fact there are people ice skating out there."

Officials are watching conditions on the ice to ensure that it's staying locked in and maintaining about 10 inches of thickness.

Warmer weather this winter delayed the opening of the caves. During last year's cold and long winter, more than 138,000 people visited the caves. It was the first time they'd been accessible to the public in five years.

"When the water starts getting really cold and icing up, you have waves splashing up and into the caves, that creates icicles and formations from the bottom," Van Stappen said. "Then there's also seepage that comes out of the pre-Cambrian sandstone cliffs."

There's a new event fee to visit the caves, this year. The $5 charge for visitors 16 and older is to help offset the costs of managing the crowds that park officials anticipate.

Officials say the caves will stay open until the winds begin to break up the ice.

Last year the caves closed on March 17. The park service says they probably won't last that long this year.

Getting to the caves requires a mile walk over Lake Superior ice. Visitors are encouraged to wear sturdy, waterproof boots with ice cleats on the soles, and use ski poles to prevent slipping.