Ahead of what organizers say will be one of the largest marijuana-themed celebrations in the world, a number of officials in Denver are looking to this weekend’s events with something between wariness and dread.

Take, for instance, the city’s police department, which plans to have extra officers on hand to monitor the large, marijuana-puffing gathering in Civic Center park known as the “420 Rally.” Although public marijuana consumption remains illegal in Colorado, a department spokesman says the beefed-up presence will nonetheless try to maintain a low profile.

“Our biggest goal is to ensure everyone is safe in this environment,” Denver police spokesman Sonny Jackson said. “We’ll have the necessary number of officers to ensure the safety of the public.”

The rally takes place every year on April 20 — a day marijuana enthusiasts regard as a cannabis holiday they call 4/20. It could draw tens of thousands of attendees this year, as the first major public event around marijuana in Colorado since voters legalized use and limited possession of the drug last year.

Rally organizers are expecting so much interest in Saturday’s event, they included Sunday this year, and a number of other marijuana-centric concerts, exhibitions, tours and events will also take place in the city throughout the weekend.

At last year’s rally, police took a mostly hands-off approach, making 54 arrests , 49 of which were for misdemeanor possession of marijuana. Four others were arrested for having drug paraphernalia and one for drinking in public.

“”We will exercise our discretion in the enforcement of public consumption,” Jackson said. “Officers have discretion as to how they enforce it.”

A spokeswoman for Denver Health Medical Center wrote in an e-mail that the hospital is not anticipating a rush of patients experiencing marijuana-related problems. But others have different worries about the problems the events may cause.

The head of Arapahoe House, one of the state’s biggest drug-treatment providers, said parents should talk with their kids ahead of the event, fearing that the public celebration of marijuana will send the wrong message. Arapahoe House has created an online guide to discussing marijuana’s dangers with kids.

“Parents may think their kids are immune to the landscape, but it’s a risk that shouldn’t be ignored,” Arapahoe House CEO Art Schut said in a statement. “They are going to be curious.”

Meanwhile, Denver City Council member Charlie Brown has another concern about the rally: It’s treatment of Civic Center park’s grass. With the ground likely to be squishy from this week’s snow, Brown fears rally attendees could tear up the turf.

“There’s going to be some cost involved, and I don’t think the taxpayers should have to bear that cost,” Brown said.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold