When National Weather Service meteorologist Dave Snider saw an uptick in vehicles stopping by the service's Anchorage headquarters near Kincaid Park starting on Friday, he knew why they were coming by: Pokémon was a go.

Eventually, Snider said Monday, he decided to do something about it — putting a sign outside the building warning that "Pokemon trainers must not trespass on federal property." Snider posted a photo of the sign on his Instagram account along with the comment, "Pokemon go! No? Really. Go."

"We've seen a few more cars pulling in here than normal that aren't coming in for weather information," Snider said. "While I was putting the sign out, I saw two cars come in just in that time."

"Pokémon Go," a Nintendo game released Wednesday, has been taking the world's smartphone base by storm. According to The Washington Post, the augmented-reality game — in which players try to capture "pocket monsters" projected on their smartphone screens in real-life locations based on GPS data, then meet at spots designated as "gyms" to train them — is already installed on more smartphones than the dating app Tinder.

Snider said Monday afternoon that the building has also been featured in a similar game, "Ingress," also developed by "Pokémon Go" creator Niantic Labs. In "Ingress" the headquarters is a "portal," which members of that game's two opposing factions can visit to temporarily seize control of it in-game.

According to Snider, an intermittent player of "Ingress," Niantic reused many of the GPS points plotted for "Ingress" in "Pokémon Go."

"I'm pretty sure it's a training gym," Snider said. "My son has (Go) on his phone and he pulled it up."

The initial craze over the game has had its dark side nationwide, with police in Missouri and Nebraska investigating instances of players being robbed by suspects who had staked out "Pokéstops" designated within the game, then waited for players to approach them. A Wyoming woman even encountered a body along the Wind River while playing.

Those ramifications of the game apparently hadn't yet reached Anchorage over the weekend. Police spokeswoman Renee Oistad said Monday that dispatchers hadn't gotten any calls related to the game.

"We're not hearing about robberies or people walking into traffic or anything," Oistad said.

Back at the weather service, Snider said he added a second sign outside the building to help "Pokémon Go" players avoid the building's own dark spot: the septic field out front.

"They were just camping in it before," Snider said.

Asked if he plans to start playing "Pokémon Go" himself, Snider deferred the monster-catching duties to his son.