"UEA," the annual teacher professional day in Utah hosted by the Utah Education Association, is coming this weekend, and officials at at least two of the state's national parks are warning visitors to expect heavy crowds for the weekend.

Arches and Canyonlands national parks expect to see unusually busy weekend traffic for this time of year, as all of Utah's public schools enjoy a four-day weekend starting Thursday.

UEA weekend 2015 saw visitation jump 15 percent over the preceding four-day weekend, resulting in overflowing parking lots and long waits at entrance stations, said officials at Arches and Canyonlands national parks.

"Traffic at Arches during such busy time frames can back up onto U.S. 191, creating a serious safety hazard. In addition, vehicles in the entrance line at the Island in the Sky district of Canyonlands National Park frequently experience long wait times as visitors bypass the lines at Arches and head to Canyonlands instead," they said. 

During the UEA weekend, park officials recommend visitors enter the parks before 9 a.m. or after noon to avoid entry line wait times that may exceed one hour.

To help minimize wait time at the parks' entrance stations, park officials ask that vehicles keep pace with traffic in the line. Current pass holders and returning visitors should have passes and identification ready. Credit cards are preferred for buying new passes.

If the parks reach capacity or entry lines into Arches begin to impact traffic on U.S. 191, vehicles may be restricted from entering until space becomes available.