The majority of Massachusetts was under a “red flag” warning Wednesday as forecasters cautioned that dry ground conditions and gusting winds could turn a small fire into a catastrophe.
“I tell folks here in Massachusetts we have a beautiful landscape and we want folks to enjoy the recreational opportunities that our open lands and our wild lands provide,” said David Celino, the state’s top forest fire official. “However, when we’re in conditions like this, we ask the public to maintain that heightened situational awareness.”
There have been 80 wildland fires in Massachusetts in the past week and 257 this year, Celino said.
Twenty brush fires were reported in the past two days, including one in Burlington that damaged cars and threatened to spread to an apartment building and two homes before it was brought under control.
Celino, chief fire warden for the state’s Bureau of Forest Fire and Forestry, oversees its contribution to the National Weather Service’s “red flag” warnings by tracking how dry woodlands and forested areas are. Those conditions are added to observations about windspeed and precipitation to generate the alerts.
The weather service defines a red flag warning as a combination of strong winds, relative low humidity, and warm temperatures that can “contribute to extreme fire behavior ... Any fires that start today will spread quickly and will be difficult to contain.”
Wildland fires are defined as blazes that threaten at least one-tenth of an acre of green space. But that doesn’t mean the current danger, an annual spring occurrence, only concerns exurban areas: 60 percent of developed areas in Massachusetts abut forested grounds, Celino said.
“The traditional springtime fires in New England are not going to be fueled by large dead trees. It’s going to be the shrubs, the leaf litter that has not greened up,” Celino said. “We’re seeing the traditional dry air masses move in with wind behind them and low humidity. But the vegetation has not yet gotten to the point where it’s taken up moisture and turning green.”
According to the weather service, the earliest chance for significant precipitation in Massachusetts is Sunday and Monday, although forecasters cautioned the weather picture remains unsettled.
Celino said the tally of wildland fires excludes house or structure fires.
“We’re talking about fires that typically escaped containment, a campfire that escapes or a burn permit that escapes,” he said. “Something that actually goes out of control.”
The Department of Conservation and Recreation has 42 fire towers, and Celino said about 23 are currently staffed, with the goal of quickly alerting local fire departments so that small fires do not grow.
“It’s been all hands on deck,’’ he said.
Brush fires were reported Wednesday afternoon in Brockton, Pepperell, and Plymouth, according to officials.
The Plymouth fire, which broke out about 2 p.m., burned two acres off Route 3 before being brought under control about 45 minutes later, the department said in a statement.
In Pepperell, the first brush fire was reported at 12:50 p.m. and was caused by a power line. It was knocked down in 45 minutes, according to the Pepperell Fire Department.
The second brush fire in Pepperell began at 2:10 p.m. and covered multiple acres, according to Pepperell fire. Multiple neighboring communities assisted, and it was put out by 3:46 p.m., the department said.
According to the weather service, the red flag warning covers the entire state except for Martha’s Vineyard. It will remain in effect until 7 p.m. Wednesday, when winds reached 30 mph.
Temperatures will remain elevated on Thursday and Friday, but winds will abate.
“The potential exists for the first 80 degree day across much of Southern New England away from the coast on Thursday,” forecasters said. Wednesday.
In New Hampshire, forecasters reported that while gusting winds are concerning, ground cover remains damp, easing concerns.
“Fuels remain on the damp side in spite of near-critical to critical fire weather conditions,” forecasters wrote. “Conditions will remain dry through the end of the week, but with lighter winds.”
Jake Wark, spokesman for the Massachusetts Department of Fire Services, said research shows that human activity, such as operating a burn pit or not watching a campfire closely, is behind almost all outside fires.
“Wildland fires can easily become large scale, long-term fire events that are time and labor intensive,” Wark said. “They are also a drain on local resources where local fire departments also have a community worth of emergencies to respond to.”
Correspondent Grace Gilson contributed to this report.
John R. Ellement can be reached at john.ellement@globe.com. Follow him @JREbosglobe.