U.S. Southwest power failure from solar flares? Probably not

Officials warn U.S. Southwest residents to go easy on their electric usage this weekend, after restoring power to millions following Thursday’s power outage.

Officials in California, Arizona and New Mexico today are warning residents and businesses to go easy on major appliances such as air conditioners – or avoid using them – following a power outage that left millions without power on Thursday, September 8, 2011.

Power was restored to most people on Friday, September 9, but officials say the grid is still extremely fragile.

This week’s solar activity

Thursday’s blackout happened in a week when the sun was very active. The sun produced four solar flares and three coronal mass ejections from September 6 to September 8, 2011. However, the blackout in the U.S. Southwest is not thought to be related to this week’s solar activity. Here are two things to consider:

  • The U.S. Southwest blackout occurred before the effects of the solar activity had a chance to travel the distance between the sun and Earth.  Coronal mass ejections, or CMEs, are great clouds of solar materials that take several days to get here following their release from the sun at a time of high activity.  On Thursday, they weren’t here in full force.
  • According to NASA, computer models suggest the CMEs from this week’s solar activity will not strike Earth squarely, even when they do arrive.  Instead, the models indicate these great clouds of solar materials will give Earth only a glancing blow.  All along, NASA has been saying not to expect negative impacts to power grids from these flares. So further negative impacts to electric grids from solar activity are not expected, even as the effects arrive fully across this weekend.

Thursday’s blackout was reportedly caused when an Arizona Public Service Co. worker was switching out a capacitor, a device which controls voltage levels, outside Yuma, Arizona, near the California border. According to an AP story published at ajc.com this morning:

Shortly after, a section of a major regional power line failed, eventually spreading trouble further down in California and later Mexico, officials said. Thursday’s blackout has puzzled authorities and experts and was a reminder that the nation’s transmission lines remain all too vulnerable to cascading power failures.

It’s true that the grid can be especially vulnerable at times of high solar activity. A power outage like the one in the U.S. Southwest this week indicates that a is grid running at or near capacity, leaving little room for geomagnetic fluctuations due to a solar storm. Solar effects are not likely this weekend, according to NASA, but it can happen, as it did in Québec in March of 1989. A geomagnetic storm on March 13, 1989, caused the Hydro-Québec power failure, which left 6 million people in the Canadian province of Québec without power for nine or more hours.

Of course, as with all science, computer models projecting into the future have a chance of being wrong. We will see what happens!

Bottom line: Power was restored to millions in the U.S. Southwest on Friday, September 9, 2011, following a widespread failure of the electric grid that left millions without power for a time. The grid failure was not related to activity on the sun earlier this week. Officials are warning those in the U.S. Southwest to go easy on their electric usage this weekend. This incident prompted many to wonder about the fragility and vulnerability of the U.S. electric infrastructure as a whole.

Ryan Teal on the Arizona/California border contributed to this story.

What you need to know when the power goes out unexpectedly, from the CDC

Electricity is restored in Southwest but officials wonder what went wrong, from Detroit Free Press.

Visualizing the U.S. electric grid from NPR

A fourth solar flare from Sunspot 1283!

Bill Meehan on using GIS to help create a smart grid

Deborah Byrd

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