Tens of thousands of marijuana fans are expected to flock to San Francisco's Golden Gate Park this Friday, April 20, marking one of the many annual celebrations of cannabis that will take place around the country.
This year's 420 event comes several months after sales of recreational marijuana became legal in California, and as cannabis advocates and industry leaders push for a growing cultural acceptance of pot use.
"Many who participate in these events will take the time to celebrate their recent victories," said Paul Armentano, deputy director of the National Organization for the Reform of Marijuana Laws (NORML). "But there will continue to be a movement afoot to try and bring normalization to the way adult users of cannabis are treated."
Marijuana advocates want to spread legalization to other states and protect dispensaries from federal enforcement.
"The passage and enactment of Proposition 64 is not the finish line. In many ways it marks the beginning of the race toward cannabis freedom," Armentano said.
The 420 celebrations around the nation have traditionally been used to advocate for marijuana legalization and to celebrate pot.
"Now we're at a place where the industry needs to take this holiday to show that the industry is responsible," said Josh Drayton, a spokesman for the California Cannabis Industry Association. "The evolution of cannabis regulation and culture in California has changed, and I believe the 420 celebrations need to evolve as well."
The change in the law, coupled with the fact that this year's event falls on a Friday with the weather forecast to be mostly sunny, could bring very large crowds to Hippie Hill in Golden Gate Park.
Organizers plan to spend hundreds of thousands of dollars on permits, 60 private security guards, more than 180 portable bathrooms and cleanup work in the park and some of the surrounding neighborhood areas, said Alex Aquino, a Haight Street merchant who began producing the 420 event last year.
A dozen companies, including several cannabis businesses, are sponsoring the event.
Aquino says his goal is to keep the party -- which includes a music concert -- safe and clean. His team plans to put up a long fence line around portions of the park. Two ambulances will be on-site during the event.
"It's probably going to be a bigger celebration because it's legal," Aquino said.
What's not legal is to smoke marijuana in public, but that law will be violated often at Hippie Hill Friday afternoon. In fact, the event's website features several photos of smoke wafting into the air.
Aquino stresses that sponsors will be barred from selling pot at the event as well.
San Francisco Recreation and Park officials say working with Aquino last year worked well.
"The results were a much safer event, a cleaner park and cleaner streets," said Connie Chan, a Rec and Park spokeswoman.
The party traditionally brings out a significant number of police officers, traffic control officers and public works crews. In all, at least eight city agencies will be involved in helping to put on the event.
The San Francisco Municipal Transportation Agency plans increased Muni service to and from areas around Golden Gate Park for the event.
"We'll have a lot of people out there and a lot of service to make it as smooth as possible," said SFMTA director Ed Reiskin. "There are people who are not going to or from 420 but are just trying to get around town, trying to get home at the end of the day, and we'll do our best to manage for that."
Several streets, including parts of John F. Kennedy Drive, will be closed, starting early Friday morning.
There will be extra city cleanup crews on hand, according to Larry Stringer, San Francisco's Public Works deputy director for operations.
"We've done this for a few years now, so we have a plan that's pretty well set," Stringer said.
Supervisor London Breed, who represents the area, plans to announce the city's plans for handling this year's event during a press conference on Wednesday, the same day fencing will be installed around the area of the party.
Friday's event starts at 9 a.m., the music starts at noon, the party's climax will of course take place at 4:20 p.m, and the event is set to end at 6 p.m.
KQED's Muna Danish contributed reporting to this article.