CNN  — 

A wildfire near Boulder, Colorado, prompted an evacuation warning for nearly 20,000 people Saturday evening.

“Evacuation areas include 19,000 people and 8,000 homes,” the Boulder Office of Emergency Management tweeted.

The NCAR Fire broke out Saturday afternoon. It was just 123 acres by Saturday evening, but not contained at all, officials said.

“The state has deployed two firefighting aircraft, including a single-engineer tanker and Type 2 helicopter, and stands ready to assist with the response,” said Gov. Jared Polis in a statement. “We will continue to monitor this evolving situation.”