AMHERST — A brush fire that consumed more than 1½ acres of woods on the Orchard Hill section of the University of Massachusetts campus Monday evening, and approached equipment associated with a cellphone tower, appeared to be fully extinguished Tuesday morning.

Amherst Fire Department Acting Fire Chief Lindsay Stromgren said Tuesday that after about three hours of battling the blaze Monday, with nearly three dozen people on scene, and returning Tuesday morning to put out hot spots visible during the daylight, the fire had been put out.

The fire, which firefighters responded to around 5:30 p.m., burned across the wooded area that separates UMass dormitories from a campus academic area, and within about 30 feet of the Orchard Hill Observatory. It also burned dead trees and some branches on living trees through the fence of the cellphone tower on the campus side, but firefighters were able to prevent it from damaging the electronics and a diesel generator at the base of the tower.

The response included about two dozen on-duty and off-duty Amherst firefighters and Pelham Fire Department personnel with a tanker, along with the state’s Department of Conservation and Recreation.

The work included putting down significant amount of water and raking a line. With no fire hydrant close, the Pelham tanker was to replenish the water on scene.

No cause has been identified.

“We will never have a definite cause, but the suspicion is a discarded cigarette,” Stromgren said, observing the area is a popular place for people to walk and cigarettes have been a leading cause of similar fires. Stromgren said people are largely abiding by prohibitions on outdoor fires and disposal of ashes.

The fire comes as the state’s Energy and Environmental Affairs Secretary Rebecca Tepper on Wednesday elevated the Western, Connecticut River Valley, and Southeast regions to a Level 3 — Critical Drought, joining the state’s Central and Northeast regions. There have also been continued red flag warnings due to the high winds and dry conditions.

The drought level requires detailed monitoring of drought conditions, continued coordination among state and federal agencies to communicate the implementation of water use restrictions, declaration of bans on open burning, engagement with municipalities including local hwealth boards, providing technical outreach and assistance to water suppliers and affected municipalities.

“Massachusetts is experiencing critical drought conditions that are fueling unprecedented and destructive wildfires across the state,” Tepper said. “Climate change is reshaping our region’s weather patterns, resulting in warmer and drier fall and winter seasons. Water conservation is more important than ever. We urge municipalities, residents, and businesses — including those with private wells — to help us reduce stress on our water systems. We need to work together to ensure we have enough clean drinking water, protect wildlife habitats, and maintain effective fire control. Every small effort counts.”

Stromgren said he is hoping for some reasonable rain and precipitation on Thursday, which would at least temporarily calm things down for area firefighters.

Over the past 30 days, most of Massachusetts has received less than an inch of rain, which is 3 to 4½ inches below normal.

As of Tuesday, there are 37 active wildfires across the state and, since Oct. 1, the hundreds of wildfires, including a large one in Northampton, have burned more land in the state than in a typical year.

“We’re reminding all residents to follow the state and municipal guidance on fire protection because in the current drought conditions any outdoor fire is likely to catch, spread, and threaten people and property,” said State Fire Marshal Jon M. Davine. “Every firefighter battling a preventable wildfire is one who can’t respond to a house fire, car crash, or medical emergency.”

Scott Merzbach can be reached at smerzbach@gazettenet.com.