Why did Irma cause such extensive outages in South Florida?
Some of our customers, and even a couple of fellow meteorologists, have asked why Hurricane Irma caused such extensive power outages in Palm Beach, Broward and Miami-Dade counties, when the sustained winds in the tri-county area did not exceed category one strength.
While Irma made landfall as a category 4 storm in the Florida Keys, its strong winds pounded southwest Florida. Southeast Florida experienced gusts above 100 miles per hour, but a lower level of sustained winds.
What distinguished Irma from past storms was its size. Irma was a vast storm – the size of Texas – that impacted all 27,000 square miles and 35 counties of FPL’s service territory, including the tri-county area. Unlike previous storms, in which we could focus on restoring a particular region, responding to Irma required us to deploy our resources across the entire state.
Also, Irma was not a fast-moving storm. It impacted the tri-county area for at least 12 hours. The prolonged exposure to tropical storm and hurricane force winds amplified the damage of those winds. To put that into perspective, Hurricane Wilma swept through the entire peninsula in only five hours.
Irma spawned tornadoes and probably other small-scale features of enhanced winds that created pockets of catastrophic damage in the tri-county area.
But the most damaging aspect of Irma was not so much the level of wind, but what stood in its path. Trees and vegetation caused most of the outages. Over the past decade, FPL has invested more than $3 billion to strengthen our electric grid and according to our early estimates, it performed very well in the storm. You can harden a power pole, but you can’t stop a tree from blowing into power lines. FPL proactively clears vegetation from 15,000 miles of lines each year. We also rely on the communities we serve to do their part to trim trees. With Florida’s year-round growing cycle, trees grow quickly, and Irma drove that vegetation into the power lines.
Mother Nature’s wide-spread pruning of South Florida’s trees – the first in over a decade – and the power outages that resulted from that clearing, serve as a reminder about why year-round trimming is so important for all of us. Not only does trimming trees keep our homes and communities looking their best, it also helps reduce power outages and restoration times following a storm.