Federal Energy Regulatory Commission 

June 21, 2012 

Open Commission Meeting 

Staff Presentation 

Item A-3

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www.FERC.gov 

“Mr. Chairman, Commissioners: I am pleased to present a summary of the FERC/NERC Staff Report on 

the October 2011 Northeast Snowstorm Outages. 

As you know, this was a joint inquiry with the North American Electric Reliability Corporation. The 

team also included a Northeast Power Coordinating Council representative. We thank NERC and NPCC 

for their contributions to the inquiry. I would also like to recognize the team members from the Office 

of Electric Reliability who are not present: Justin Cunningham, Andrea Scott, and Norris Henderson. 

The report is based on conclusions of staff and does not represent the views of the Commission, the 

Chairman, or any Commissioner. 

During the course of the inquiry, the team issued detailed data requests to many utilities and other 

entities throughout the Northeast, made site visits to transmission facilities in New England, and 

interviewed representatives of a number of affected entities. The team also conducted numerous 

outreach meetings and calls with agencies in affected states and with electric industry trade 

associations 

The purpose of the inquiry was to look into whether any FERC-jurisdictional facilities or NERC 

Reliability Standards were implicated in the power outages caused by the October 2011 snowstorm. 

Therefore, the inquiry focused on the storm’s impacts to the transmission system. We did not examine 

the storm’s impact on distribution systems, or make any recommendations relating to distribution 

facilities. 

The snowstorm that hit the Northeastern United States on October 29-30, 2011 was an unprecedented 

Fall weather event, breaking records across the New England and Mid-Atlantic states. Up to two-and-ahalf feet of heavy, wet snow fell on trees that had not yet lost their leaves and that were rooted in 

ground that had been saturated by an unusually warm, rainy summer. The weight of the snow, in 

combination with the soft ground, caused many healthy trees to become uprooted and fall on power 

lines. More than three million homes and businesses from Pennsylvania to Maine were without power as 

a result of the storm. 

The majority of these outages were the result of damage to the distribution system. Only about 

130,000 of the customer outages – less than 5% – were the result of transmission facility outages. 

Inquiry staff identified 74 transmission line and 44 transmission substation outages that lasted 10 or 

more minutes. These outages occurred in six states: Connecticut, Massachusetts, Maine, New 

Hampshire, New York, and Rhode Island. These were mostly 115 kV lines, but there were one 138 kV 

and three 345 kV line outages. 

Although this number of transmission facility outages constitutes a significant transmission event, the 

outages did not threaten the stability of the bulk power system. 

These transmission outages were overwhelmingly caused by tree contact. Fifty-five of the 74 

transmission line outages -- that is about 75% -- occurred when snow-laden trees or branches fell onto 

transmission lines. Most of these trees fell onto lines from outside the utilities’ rights-of-way. But 

13 transmission line outages resulted from trees falling from within a utility’s right-of-way -- that is, 

the area the utility has the right to maintain, although in some cases those rights may be limited. 
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Because the vast majority of transmission outages were caused by tree contact, we evaluated the 

applicability of the Commission-approved transmission vegetation management reliability standard, 

FAC-003-1, to the event. We found that the standard had limited applicability here, mainly because 

the vast majority of impacted transmission lines were operated at 115 kV, and FAC-003-1 does not 

apply to any lines under 200 kV unless designated as critical to reliability by the owner or Regional 

Entity. In fact, FAC-003-1 applied to only one line damaged by tree contact during the storm, a 345 kV 

line in Connecticut. 

As to recommendations, staff did see areas where utilities could take steps to improve transmission 

system reliability in future snowstorms or similar weather events. Therefore, the report makes several 

recommendations regarding utility best practices. The report’s two key recommendations relate to 

vegetation management. 

First, where appropriate, the report recommends that utilities take targeted steps to address off-rightof-way danger trees (that is, trees so tall and so close to facilities that, if they fell, would contact a 

transmission line). We recommend that utilities focus on identifying danger trees outside the rights-ofway of lines over 200 kV and other critical transmission lines and work with stakeholders to develop a 

strategy for addressing the danger trees that pose the greatest threat to bulk-power system reliability. 

Second, where feasible, the report recommends that utilities employ the industry best practice of 

ensuring danger trees are not present inside their rights-of-way. We also recommend a targeted 

approach here: utilities should identify areas where elimination of danger trees inside the right-of-way 

is feasible and would increase reliability, and then prioritize their efforts on rights-of-way where 

critical facilities are located. 

The report recognizes that vegetation management is often a sensitive issue and utilities should work 

cooperatively with landowners in implementing these recommendations. 

We thank you for the opportunity to present this brief summary of the inquiry report.”