While many students enjoyed their winter vacations in warmer locales, temperatures in New Haven plunged near zero two weeks ago. For many in the Elm City, the cold temperatures were uncomfortable. But for Yale’s Central Power Plant, they were much worse.

In a bizarre chain of events, the chilling temperatures led to a massive explosion at the power plant early in the morning on Friday, Jan. 5, only to be followed by an unrelated two-alarm fire in another part of the plant just three hours later.

No one was injured in the accident and the plant is expected to be fully repaired by today, Yale officials said. Both the explosion and the fire were unprecedented.

“It was like a perfect storm,” said Thomas F. Starr, the manager of the Central Power Plant, located on the corner of Tower Parkway and Ashmun Street and adjacent to the Swing Space dormitory, where displaced Jonathan Edwards College students are living this year while their regular housing is renovated.

At the time of the accidents, Connecticut was suffering through some of the chilliest weather in recent memory, with overnight lows reaching into the single digits. As part of an agreement with Southern Connecticut Gas, the power plant — which runs on natural gas — switches to backup fuel to relieve the strain on SCG’s gas network when it is at high capacity, such as in the case of especially cold temperatures.

As a result, the plant switched off its natural gas lines two weeks ago and began powering its three massive turbines using reserves of diesel fuel held in tanks at the plant, according to power plant officials.

Then something went wrong. At about 2:15 a.m., a violent explosion ripped through the second of the plant’s three turbines, apparently the result of a fuel leak. The explosion was so intense that it blew out several of the doors on the turbine’s metal enclosure, witnesses said.

If any workers had been in the vicinity at the time, they likely would have been seriously injured, if not worse, Starr said.

The explosion damaged two of the three turbines in total, so the plant fired up two temporary, backup boilers that are housed in large wooden sheds along Tower Parkway.

But for the plant’s crew, the strange morning did not end at the explosion.

No more than three hours later, one of the two temporary boilers somehow caught fire, sending flames shooting high into the air across the street from the Hall of Graduate Studies. Frightening pictures of the blaze led local morning newscasts, which just two weeks earlier had captured another New Haven fire, on the other side of downtown, that destroyed much of a city block to the southeast of the Green.

By sunrise, fire crews had contained the blaze, which started in a large wooden shed housing a temporary boiler, New Haven Fire Marshal Joseph Cappucci said. The fire, which was reported around 5:30 a.m. did not spread to the main building of the plant, and most of the damage appeared to be contained to the roof of the building housing the temporary boiler, he said.

The distinctive stone lions that guard the power plant’s gates survived the inferno unharmed.

While the fire appeared serious to a layperson — images of the flames on News Channel 8 seemed to indicate that an inferno had consumed much of the front of the plant — by the time the smoke cleared, it was clear that most of the damage was limited to the roof of the boiler enclosure, fire officials said.

“It was like, ‘Well, gee, this really wasn’t so bad,’” Starr said.

By midday, Grove Street had re-opened, and the fire crews had decamped from the scene of the fire. A Yale spokeswoman said that afternoon that the Office of Public Affairs had not received any inquiries into what had happened at the power plant.

By this weekend, fire officials had concluded that the blaze was the result of a defect in the boiler, Yale Fire Marshal Michael Johns told the News. An investigation indicated that some superheated gases leaked out of the boiler’s stack and came into contact with insulating material on the inside of the boiler’s wooden enclosure, Johns said.

Despite the turn of events at the plant, most of the Yale campus was unaffected by the situation, officials said. The steam-production capacity was limited at times, resulting in a steam equivalent of a brownout in some parts of campus, but the plant managed to press on despite the dueling emergencies, Starr said.

“Our operations staff never skipped a beat — most customers saw no interruption in service,” he said.

And, better yet, as far as injuries were concerned, “Not even a splinter was reported,” Starr added.

The power plant, whose brick smokestacks can be seen from around campus, was built in 1918. It received an extensive, $70 million renovation and addition in 1998. While many Yale students may not notice the structure, the plant is home to the largest chiller in the state of Connecticut.

While Friday’s fire was easily contained, New Haven is still reeling from its largest fire in decades. A massive inferno engulfed the old Kresge department store on Dec. 12, temporarily displacing 100 residents and all but shutting down traffic downtown on a busy weekday.

Demolition work is continuing on the buildings devastated by that fire, which impacted scores of businesses on the block southeast of the New Haven Green bounded by Church, Chapel, Orange and Center streets.