(AZ Central) -- Grasshopper swarms in and around Albuquerque, N.M., are so thick they are appearing on National Weather Service forecast radar.
"At first there was some question about what it was," said David Craft, a meteorologist with the NWS office in Albuquerque, who said the swarms first started appearing around Memorial Day.
On Friday, meteorologists determined the mysterious objects were indeed the grasshoppers that residents had already seen for weeks around town.
Unlike precipitation, the swarms of grasshoppers did not have clean edges and also showed up for hours at a time on the radar, Craft said.
"Showers and thunderstorms come up and go down. They don't last long," Craft said.
Although grasshoppers are native to the region, an outbreak of this magnitude hasn't appeared in 20 years, said Paul Smith, manager of the urban biology division at the Albuquerque Environmental Health Department.
Heavy rainfall late last year increased the vegetation on which grasshoppers feed. Coupled with a mild winter that did not kill off as many eggs, the grasshopper population burgeoned.
"Coming back into a drought situation, now there's very little vegetation, so they're moving into the city where there's water," Smith said.
The grasshoppers are harmless to humans. They don't bite or carry diseases, but they can be a nuisance.
"When people are jogging or biking, they smack people in the face and it can hurt," said John Garlisch, extension agent at the Bernalillo County Cooperative Extension Service.
Plants are not safe, though. Grasshoppers tend to eat tender plants and vegetables. In rural areas, farmers are starting to see damage to their melon, chili and pepper crops, but it's too soon to determine just how extensive that damage will be, Garlisch said.
For the average homeowner, pesticides are discouraged because they only target the insects present in the moment and not the many that will repopulate the area, Garlisch said. The best protection for plants is to keep them covered until this outbreak is over, he added.
How long the infestation will last is unclear. Smith said he expects the grasshoppers to start dispersing in the next two to three weeks, as the insects run out of food and then are eaten by predators.
In the meantime, all people can really do is be patient.
"Catch them and go fishing. Dip them in chocolate," Garlisch said. "Have fun with it."