Events and circumstances in which squirrels have caused major power outages
Squirrel running along utility lineA squirrel can disrupt a power system if its body becomes a current path between electrical lines such as those seen here.
Electrical disruptions caused by squirrels are common and widespread, and can involve the disruption ofpower grids. It has beenhypothesized that the threat to the internet,infrastructure and services posed bysquirrels may exceed that posed bycyber-attacks.[1] Although many commentators have highlighted humorous aspects of the concern, squirrels have proven consistently able to cripplepower grids in many countries,[2] and the danger posed to theelectrical grid from squirrels is ongoing and significant.[3][4] This has led to tabulations and maps compiled of the relevant data.[5]
Electrical disruptions caused by squirrels are common and widespread. BetweenMemorial Day (May 27, 2013) and August 31, 2013, at least 50power outages caused by squirrels (POCBS) were recorded in 24 U.S. states.[6] Cities affected by POCBS includedMason City, Iowa andPortland, Oregon.[7] Most media coverage of such events has compared the number of electrical grid shutdowns due to squirrels and those due to terrorists. Commentators often embellish and parody descriptions of the squirrels responsible for interrupting electrical service withallusions to military action or concerns, for example: "Squirrels mobilize, plot acts ofcyber terrorism against humankind—And they're not acting alone."[8] or "Squirrelus interruptus: 5 things shut down by squirrels—How can a squirrel bring a nuclear weapons site to its knees?"[7] Electrical grids are not the only types of infrastructure at risk from squirrels, but nuclear weapons sites have also been described as targets of squirrel attention.Ground squirrels have interfered with underground nuclear missile sites atMalmstrom Air Force Base in Montana. The squirrels are able to tunnel under fences, bypassingmotion detectors. Like theirarboreal relatives, they can damageelectrical cables by biting them. In addition, those that do take above-ground routes onto the base trigger thousands of false alarms each year.[7]
Squirrels damage electrical distribution facilities by tunneling, by chewing through electrical insulation, or by simultaneously coming into contact with two conductors at different electrical potentials.[9][10] Typically the animal is killed by the passage of current through its body.[11] Prevention is complicated by the ability of squirrels to bypass plastic animal guards, gnaw through insulation and squeeze through small openings into substations.[12]
Squirrel-caused grid disruption in the U.S. is monitored by theAmerican Public Power Association (APPA).[12] The APPA has developed a data tracker called "The Squirrel Index" (TSqI) to analyze the pattern and timing of "squirrel attacks" on electrical power systems. The TSqI is a metric that quantifies the rate per 1,000 customers over a period of time, and indicates two peak periods of highest "squirrel activity" or "squirrel peaking months" (SqPMS) in the year, in May–June and October–November, when disruption is greatest.[13]
This is the rate per 1000 electrical customers and squirrel related outages
According to a survey made by one security expert, the real threat to critical infrastructure located around the globe is from the squirrels. It has been discovered that squirrels are causing more damage to critical infrastructure than cyber wars launched by enemy states or organizations.[14]
Intentional damage by human terrorists is often the first concern in assessing threats to the U.S. power supply; some cybersecurity experts believe a country's infrastructure, such as its power grid, is a likely terrorist target. But according to the security researcherCris Thomas, also known by the pseudonym Space Rogue, "We've had power outages caused by squirrels in all 50 states ... [including] Hawaii, where they don't even have squirrels, but they do have chickens."[15][16]
In 1987 a 90-minute loss of power toNasdaq's automated trading computer, caused by a squirrel, affected twenty million trades.[9][17][18] Nasdaq was shut down for about 30 minutes again in 2014 by a squirrel-induced power outage.[19][20][21] Other commentators have noted that actual cyber attacks by human terrorists are much rarer than disruption caused by squirrels.[14]
John C. Inglis, the former deputy director of the U.S.National Security Agency, said in 2015 that he judged the electrical grid was as likely to be paralyzed by anatural disaster as by a cyberattack and added: "[F]rankly, the No. 1 threat experienced to date by the U.S. electrical grid is squirrels."[22][23]
Similar concerns exist in Germany, where in 2005, a "cyber squirrel" crippled the entire electrical grid south of the River Elster for an hour. This squirrel was described as "a furrysuicide bomber" ("pelzige[r] Selbstmordattentäter").[24]
Squirrels have been the cause of many power outages inPennsylvania.[n 1] Cris Thomas has said that as of January 2017[update] in the United States there have been six deaths associated with squirrel interference with infrastructure, such as downed power lines (and two with other animals).[18]
One commentator criticized the UK press for what he saw as an emphasis on "the ethnic struggle between Britain's populations of red andgrey squirrels, and the latter's demonization (as immigrants and terrorists) and threatened eradication".[43] In at least one circumstance, a physical attack by a squirrel has been characterized as a "terrorist squirrel."[44]
