The great eclipse migration has begun. And for those hitting the road late, maybe pack a lunch. Oh, and don’t forget some extra gas. You’re probably already too late for eclipse glasses or a place to stay.

Metro Denverites making the trek north for Monday’s total eclipse of the sun have already been warned of extreme traffic delays that could give a turtle time to cross the road. But drivers should also be prepared for delays at gas stations as eclipse hunters are already crowding the pumps.

“We didn’t prepare enough, apparently,” said Jean Milligan, the deli manager at Reata Travel Stop in Sterling along Interstate 76 on the way to Nebraska. “This place has been slammed.”

Normally, Milligan said he’ll make 100-110 sandwiches at the deli from 6 a.m. to 10 p.m. He had made 200 before 2 p.m. Friday.

Milligan said he was glad the travel stop had ordered extra gas and store items. But that doesn’t mean it hasn’t run out of things — namely eclipse glasses.

The Colorado Department of Transportation said some experts have predicted up to 600,000 people will be heading to Wyoming, which would double the state’s population. The agency told people to imagine six Denver Broncos games exiting at once. High traffic was expected through Tuesday — with the worst day Monday, when the eclipse takes cosmic stage.