On July 2, a blackout in the West left 2 million
people without electricity. The culprit, it turns out, was a
cottonwood tree in southeastern Idaho. Or perhaps it was the
maintenance folks who allowed this lone tree to grow so close to a
power line that electricity jumped to it. When this “flashover”
occurred on what was a swelteringly hot day, line after line
tripped out, says Corry Alsberg, who speaks for the Western Systems
Coordinating Council. Lots of electricity was moving around power
lines that day, she says, and the unusual conditions probably won’t
be duplicated.
On Aug. 10, however, the West’s
power grid failed again. This time 4 million people lost
electricity for everything from air conditioners to traffic lights,
mostly in California. Alsberg says the culprit was “random multiple
transmission line outages, most likely from overloaded, sagging
powerlines.” There was also another flashover to a tree, she adds,
“but no, this is not a trend.” The council is a voluntary group
that promotes electricity reliability in 14 Western states plus
parts of Canada and Mexico.
*Betsy
Marston
This article appeared in the print edition of the magazine with the headline A tree did it.
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