Power Lines Blog

In the Eye of the Storm: Peak Squirrel Activity

squirrel outage ticker

By Alex Hofmann, Director of Energy and Environmental Services, American Public Power Association

Updated: Monthly Squirrel Ticker 1/21/2016

Due to the changing nature of the industry, distribution system reliability is at the top of the agenda for many utilities and their customers. To improve the reliability of your system, the first step is to track your outage and reliability data. The second is to conduct analysis to help identify threats to your system. According to APPA’s eReliability Tracker, one of the top causes of sustained outages for subscribers in 2013 and 2014 was the squirrel. Fortunately, the APPA Reliability Team has been tracking squirrels and their menacing habits to help utilities in the fight against squirrel-related outages.

The most recent eReliability Tracker data indicate a pattern in the timing of squirrel attacks on distribution systems. The Squirrel Index, a customer-weighted metric that represents the rate per 1,000 customers at which squirrel-related outages occur over a period of time, confirms the hypothesized peak period of squirrel activity in the warmest months of the year.


The data from 2013 and 2014 reveal a significant ramp up, or major peak, of squirrel-related outages across May and into June of both years. If the data accurately depicts the occurrences of 2015, we can rejoice in that we made it past the first peak. However, remain vigilant and remember – they always squirrel their way back. The data suggests there may be another peak to come in October/November. This alarming trend is indicative of the growing danger squirrels are currently posing on utilities across the country. Since 2013 and 2014 both follow similar patterns, we expect to see the same peaks in the years to come.

The public power vision changes with time, but the purpose remains consistent – to provide reliable and safe electric power to our communities at reasonable costs. To ensure reliable service, it is critical to analyze trends and prepare your utility for these attacks. Knowing the peak, or high alert, months is a great strategy in preparing for the more-than-likely squirrel outages.

APPA recommends utilities track, calculate, and analyze their outage data to address vulnerabilities, as well as benchmark against industry data to help make informed decisions going forward. Visit www.PublicPower.org/Reliability for more information on APPA’s reliability programs and analysis that may benefit your utility, such as participating in our biennial 2015 Distribution System Reliability and Operations Survey to benchmark with other utilities on a national scale.

Keep a weather eye open in the wake of these squirrel peaking months!

Alex Hofmann

Alex Hofmann

Energy and Environmental Services Director