By Alan Gomez, USA TODAY
Four of the past five years, the answer has been the squirrels, says Engelman, vice president of operations for the Lincoln Electric System in Nebraska. Nebraska is not alone. Many states are grappling with a big increase in the number of power outages caused by squirrel electrocutions.
Squirrels that fry themselves on power lines and transformers cause tens of thousands of blackouts every year.
"It's serious when it causes power outages to 50-60,000 people," said Cathy Engel, a spokeswoman for PECO, which provides electricity to the Philadelphia area.
Among recent outages:
• A squirrel caused a power outage in October that shut down Merced College, southeast of San Francisco, for half the day.
• In January, a squirrel cut power to 4,500 customers in Amarillo, Tex.
• Hundreds of gallons of raw sewage poured into Mobile Bay in Alabama after a squirrel cut power to a sewage lift station there.
Stopping the squirrels is not easy.
"Those guys are awfully clever," said Tim Fox with Ameren, which provides electricity to St. Louis-area homes and businesses.
"When they want to get into something, they do," Fox said.
Squirrel guards have been placed on many transformers, but squirrels adapt to the technology, forcing the utilities to switch to different forms of what's known in the business as "wildlife abatement technology."
"Whenever we think we've got them figured out, they try something else," Engelman said.