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Seattle City Light releases East Marginal Way Storm Investigation Report; recommendations report to follow

On Friday, April 5 around 3:50 p.m., during a storm event with high winds and rain, 26 utility poles came down along East Marginal Way South in Tukwila. To ensure full accountability and impartiality, Seattle City Light requested the City Attorney’s Office coordinate an investigation with third-party consultants to determine the cause and to make recommendations for how to reduce recurrence risk in the future. The team assembled has expertise in mechanical/structural engineering, electrical engineering, wood pole strength and loading, the properties and durability of wood, the National Electrical Safety Code (NESC), meteorology, and more.

On Sept. 30, 2019, the expert consultants provided the first part of the final report, which summarizes the final causation findings (i.e., Investigation Report). Later this fall, the consultants will finalize the second part of the report, which will offer the experts’ recommendations (i.e., Recommendations Report).

As we said in the days following the event, in a commitment to transparency, City Light will share information as it becomes available. To that end, we are providing the first part of the final report now with additional information about our next steps, which will be further informed by the second part of the final report and continued consultation with the third-party experts. We will release part two once it is finalized, as well as more detailed plans as they are developed.

As you can read in the report findings, two poles in the middle of the span that went down first had advanced decay and the weather was a factor in the timing of their failure. The initial collapse of the two poles created an unstable condition for poles to the north and south, causing sequential failures of 24 other poles, including poles with no decay.

When last inspected in 2016, none of the poles that collapsed showed any signs of imminent public safety risks that would require immediate replacement. Several were rated as P2, including the two that fell first, which was categorized as the second priority for replacement back in 2016.

The investigation found that City Light’s engineering for installation of the poles and the equipment they supported was sound based on nationally adopted engineering standards. However, the report also concluded our rating system for remaining pole strength was overly broad, which limited our ability to effectively prioritize replacements, especially among P2 poles.

With these findings, we are taking immediate action to address these issues, starting with:

  • Assigning a project manager to oversee and accelerate pole replacements with an emphasis on safety, prioritizing the poles with the least strength remaining.
  • Reprioritizing existing staff resources and using the emergency contracting process to hire vendors to accelerate pole replacements.
  • Working with the Seattle Department of Transportation to expedite the permitting process.
  • Shifting funds from other capital improvement program (CIP) projects to support this work.

“Seattle City Light is committed to the safety of our community and our workers. One pole failure of this kind is too many. We are thankful that Linda and Tom Cook avoided more serious injuries when one of these poles hit their car. We appreciate the work of the investigators to identify the cause of this event and we will take the appropriate steps to avoid a similar incident,” said Debra Smith, City Light General Manager and CEO.

“This is an essential capital improvement program and I am prioritizing public safety above all else. We will redirect funds and resources from other CIP projects, which will likely be deferred. However, our direct customer services will not be impacted, and we will not raise rates to cover the costs of these efforts.”

While we jumpstart additional pole replacements, we are developing a longer-term plan to meet or exceed all industry standards on pole replacements. This includes updating our pole strength rating system and the required maintenance timeframe. The specific adjustments will be finalized once we receive the final recommendations from the third-party experts. We do not have a firm timeline for more formalized plans but commit to sharing them as soon as possible.

East Marginal Way Storm Investigation Report

East Marginal Way Storm Investigation Report Appendices

East Marginal Way Storm Report FAQ