BOSTON (AP) — Residents in parts of eastern Massachusetts woke to the acrid smell of smoke Monday as firefighters worked to extinguish several brush fires.

The National Weather Service said on the social platform X that smoke was trapped near the ground during the morning due to a “surface inversion,” which traps cooler air below warmer air. The smoke had largely dispersed by later in the day.

There have been 18 active brush fires reported statewide in the past 24 hours, the state Department of Fire Services said in a statement Monday.

A woman died in an outdoor fire at an encampment in Millbury on Saturday.

Weather conditions statewide place all Massachusetts communities at elevated risk of brush fires. State fire officials said dry leaves, dead vegetation, and other fuels are extremely receptive to ignition.

“The dry, sunny, breezy weather is great for recreation, but it also means that any outdoor fire will spread quickly and become very difficult to manage,” State Fire Marshal Jon Davine said. “We’re seeing preventable fires growing to dangerous sizes and drawing numerous resources, locally and regionally.”

Fire officials reminded residents that open burning is prohibited statewide through January and in many communities year-round. They also urged residents to avoid outdoor cooking and heating and to use caution when using power equipment like lawnmowers and leaf blowers. The engines can become hot enough to ignite dry leaves and grass.