A fast-growing wildfire in Hesperia has prompted evacuations Saturday night.

The Hesperia Fire was first reported around 6 p.m. in the 18000 block of North Highway 173, according to CAL FIRE San Bernardino.

By 8 p.m, it grew to over 300 acres. By 9 p.m., it was over 500 acres and by 10:30 p.m., it was over 700 acres.

An evacuation warning is in place for the Lake Arrowhead Estates community near Highway 173 and Arrowhead Lake Road. Road closures in the area have also been issued by California Highway Patrol.

Firefighters and air crews have responded to the scene to battle the blaze. As of 10 p.m., the fire was at zero percent containment.

The cause of the vegetation fire remains under investigation. Officials said the expansion remains wind-driven and continues burning north.

“Crews from the ground and air continue to work on permittee control, containment lines and structure protection,” said the San Bernardino County Fire Department.

A poor air quality warning due to smoke from the fire was issued by the Mojave Desert Air Quality Management District on Saturday night.

This advisory covers San Bernardino County and will remain in effect through Sunday, June 16.

“This advisory may be extended or amended further, consistent with smoke and fire behavior, firefighting efforts, NWS and air quality forecasts,” officials said.

Residents living in the area were urged to take precautions. Those most susceptible to issues from unhealthy air include children, the elderly and people with heart and respiratory illnesses.

In areas impacted by smoke or poor air, residents should:

• Consider avoiding any vigorous outdoor or indoor exertion

• Keep windows and doors closed

• Run your air conditioner if you have one – recirculation function is ideal

• Avoid using a swamp cooler or whole-house fan to prevent bringing outdoor pollutants inside.

• People with respiratory or heart disease, older adults, and children should remain indoors

More information from CAL FIRE can be found here.

On Saturday night, firefighters continued to battle the Post Fire that ignited near the 5 Freeway in Gorman. That fire has grown to over 4,400 acres.

This developing story will be updated as more information becomes available.

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