The winged insects may outnumber the humans in some parts of town, but it's not something to worry about.
"Laughlin and even into Arizona," said Jeff Knight.
"It appears as if there's a common winter bug," he says , state entomologist with the Nevada Department of Agriculture, said Thursday. "We'll have flights about this time of the year, migrations, and they'll move northward."
Nevada has seen more rain than usual this year. The state has averaged 9.94 inches of rain from January to June, nearly double the average of 5.92 inches, according to the National Oceanic and Atmospheric Administration. It's the third-bet January to June on record for the state.
For Lyft driver Jessica Palmore,
"Never see nothing like this ever!" Palmore said Friday.
"I know they are harmless, but they make me great itchy seeing them," she said.
It's not the first time these flocks of flying insects have swarmed Sin City before.
"We have records from the '60s of it happening, and I have seen it … at least four or five times in my 30-plus years, "Knight said.
When the grasshopper population gets big, that's how it triggers the insects to move to a new area, he said.
The bugs are attracted to lights, specifically ultraviolet lights, Knight said. Bright white lights are their common hangout place.
If they are worried or want to fix the bugs, they can install amber or low-UV lights. The bugs will not hurt people, though.
"They do not carry any diseases." They do not bite, "Knight said. CNN's Taylor Ward contributed to this report.
CNN's Taylor Ward contributed to this report.