Arches and Canyonlands national parks are preparing for a busy Memorial Day weekend, and are advising visitors to expect heavy traffic, crowded trails and limited parking.

“Memorial Day weekend is typically our busiest weekend of the year,” said the parks’ superintendent Kate Cannon. “We recommend patience and flexibility for visitors planning a trip to the parks.”

Visitors arriving at the parks between 9 a.m. and 2 p.m. should expect long lines at park entrance gates that could last up to an hour.

Parking lots and trails inside the parks will be very crowded. If the parks become full, staff may delay vehicles from entering the park until space opens to accommodate more people and vehicles.

“We want these entry delays to be as short as possible,” Cannon said. “To avoid being caught in a delay, we recommend people come to the parks early in the morning or late in the afternoon.”

Park rangers ask that vehicles waiting in line at the entrance gate keep pace with traffic in the line and have their payment ready. Credit cards are preferred. Current pass holders and returning visitors should have passes and identification ready. There are no toilet facilities or drinking water along park entrance roads.

Visitors should plan for their safety by packing water and snacks and wearing sturdy shoes and sun protection. Visitors are encouraged to check the parks’ websites or Twitter accounts for current entrance gate information and road conditions prior to leaving for their visit.