Debbie Altman didn’t get the housewarming party she wanted.
Instead, six weeks after moving with her husband into a single-story brick home along Route 62 in Jackson Center, she endured a microburst and 83 mph wind gusts, part of a storm system that brought a tornado to Mercer County Tuesday.
Around 3 p.m., Mrs. Altman, 53, was peering outside when her eye fell on lawn signs advertising her son’s paint company. “Should I move them?” she asked herself, anticipating the storm. Then the sky darkened as the heavens seemed to open up, she recalled. As she and her husband hurried down to the basement to wait out the storm, they caught a glimpse of their yard from a back window. Toy trucks and pieces of the grill were airborne.
“Your perfect tree is next,” Donald Altman, 61, warned his wife, referring to the enormous tree in their yard.
He was prescient: the tree was uprooted, on its side Wednesday next to a mangled white fence. All four of Mrs. Altman’s glass-top tables were shattered, and lawn chairs were carried a mile-and-a-half down the road, she said. The back porch buckled under the pressure of the wind, and some roofing was dislodged from the house.
The pair shuddered to contemplate the cost of repairs.
“It’s devastating, but at least no one was hurt,” Mrs. Altman said, adding with a sarcastic half-smile, “I guess this was our housewarming.”
Straight-line winds in Jackson Center downed power and cable lines and caused minor damage to homes, said Mercer County Commissioner John N. Lechner. Meanwhile, in Lackawannock Township, which suffered the worst of the tornado, several homes were damaged and two barns were destroyed, on Orchard Road and North Stone Base Road.
The tornado was concentrated along State Route 318 near Hoagland, from Orchard Road to Stone Base Road, according to the National Weather Service. No injuries were reported. Extreme weather from the same storm system killed four people in New York and one in Maryland on Tuesday.
The twister that touched down in Mercer County was rated an EF1 tornado, meaning it carried winds of 86 to 110 mph.
Mr. Lechner said Mercer County was fortunate to escape more severe wreckage. Penn Power and PennDOT, along with telephone and cable companies, were out Wednesday cleaning up roads and restoring power, he added. Doug Sanko, a utility lineman for Armstrong Cable at work Wednesday mending a snapped cable line in Jackson Center, said the recent spate of rainstorms had loosened up soil, which made trees fall more readily.
Power was restored throughout the county by Wednesday afternoon, said Frank Jannetti, director of public safety for Mercer County.
“The damage that’s left is private homeowners or private business with issues where trees are down or some roof damage,” Mr. Jannetti said. “We got hit hard, but we survived it.”
Tuesday’s tornado was the second in Western Pennsylvania this year, following a June 18 twister that hit Limestone in Clarion County.
Western Pennsylvania averages four or five tornadoes a year, with peak season typically falling in May and June, National Weather Service meteorologist Fred McMullen said. These tornadoes often land on the weaker end of the spectrum, categorized as EF0 or EF1. Tornadoes can be rated as high as EF5, with winds of more than 200 mph.
Between 1950 and 2013, there were 19 tornadoes in Mercer County and 16 in Allegheny County, according to National Weather Service data.
Tornadoes are strongest and most frequent in the western part of the state, with Crawford and Westmoreland counties seeing most twisters. Fewer tornadoes strike Allegheny County’s rolling hills because they opt for the path of least resistance, but no place is immune, Mr. McMullen said.
Most tornadoes in northeast Ohio and northwest Pennsylvania are aided by wind shifts coming off Lake Erie. Colder water temperatures and warm ground temperatures meet, and a breeze moves inland, forcing less dense air on the shore to rise. A boundary develops, and depending on weather conditions, this can lead to showers and thunderstorm development, which may enhance the possibility of a tornado. These lake breezes can push as far south as Interstate 80, Mr. McMullen said.
The state’s most violent tornado outbreak occurred on May 31, 1985, killing 76 people in Ohio and Pennsylvania. An EF4 tornado, the deadliest of the day, struck near Jamestown, along the Crawford and Westmoreland County line. With a 56-mile long swath of damage — moving through Cochranton, Cherry Tree, Cooperstown and Tionesta — the tornado killed 23 people and destroyed 371 homes, according to the National Weather Service.
The location of Tuesday’s tornado didn’t surprise Keith Miller, a clerk at a Sunoco on Route 16. He said the previous three twisters in the area have followed similar paths, though each has hit a different area the hardest.
By and large, though, the weather incidents are rare, Mr. Lechner said, despite the fact that a tornado seven years ago landed in his backyard: “This isn’t a tornado alley — not even close.” But Mr. Jannetti said the number of recent twisters in the county seems to indicate a pattern.
“Nineteen is a pretty big number,” Mr. Jannetti said. “We definitely seem to be the bull’s-eye for tornadoes in this area.”
In Pittsburgh, tornadoes are rare but not unheard of. In 2007, a tornado touched down in Sheraden. In 2003 and 1998, tornadoes hit Mount Washington. Tornadoes also struck the city in 1976 and 1944.
The storm that battered Mount Washington on June 2, 1998 was particularly ferocious, sending at least 16 people to hospitals, though no one was killed. At least 14 tornadoes swept through the region that night, accompanied by thunder, lightning, severe rain and quarter-inch hail.
Stephanie McFeeters: email@example.com or 412-263-2533. On Twitter: @mcfeeters. Isaac Stanley-Becker: firstname.lastname@example.org or 412-263-3775. On Twitter: @isb_isaac.