On Tuesday afternoon, the National Weather Service in Miami issued a warning to locals about the danger of falling iguanas.

As the East Coast shivers in winter’s icy grip, even balmy Florida is seeing temperatures 15 degrees below average. And while people bundle up or stay inside, the local reptile population is not so well-equipped to weather the cold. At 50 degrees Fahrenheit, the iguana population becomes notably lethargic — below 45, they cease to function altogether.

“This isn’t something we usually forecast,” NWS Miami tweeted early Tuesday afternoon, “but don’t be surprised if you see Iguanas falling from the trees tonight as lows drop into the 30s and 40s. Brrrr!”

Jan 21 – This isn't something we usually forecast, but don't be surprised if you see Iguanas falling from the trees tonight as lows drop into the 30s and 40s. Brrrr! #flwx #miami pic.twitter.com/rsbzNMgO01 — NWS Miami (@NWSMiami) January 21, 2020

In order to survive, iguanas will become dormant when their environment grows too cold to sustain their normal functions. As their bodies retreat into a sort of preservative coma, they may even appear dead. Since they typically prefer sleeping in trees, the “cold-stunned” creatures often drop from the branches when the aforementioned temperature threshold is crossed.

Iguanas are not small animals, and their up to five-foot bodies can pose a real hazard to pedestrians and drivers when they unexpectedly fall from above. Luckily, the bigger ones seem a bit more tolerant of the cold. “The temperature threshold for when iguanas begin to go into a dormant state depends greatly on the size of the iguana,” explained Zoo Miami Communications Director Ron Magill. “Generally speaking, the larger the iguana, the more cold it can tolerate for longer periods.”

In one sense, however, the cold snap could provide an unexpected benefit: Florida’s iguanas are considered a widespread invasive species, and an extended drop in temperature could help thin the population. If temperatures continue to hover below the 50-degree bottom line for iguana activity, many of them will simply perish.

“I do know that there are several iguana hunters that are looking forward to this upcoming cold front as it will certainly facilitate them removing these invasive reptiles from the South Florida environment as they will not be able to run away!” Magill said.