As many as 24,000 San Diego Gas & Electric customers — including several local school districts — were without power on Tuesday after the company made the rare decision to shut off power in parts of the county as heavy Santa Ana winds added to an already high risk of wildfire.
The utility shut off power in rural communities like Descanso and Dulzura and in more heavily populated areas like San Marcos and of course the Del Dios area around Lake Hodges in Escondido.
We talked to Steve Vanderburg, a meteorologist at SDG&E and Colleen Windsor, an SDG&E senior communications manager, to get a better idea of how and why the company takes these measures, often in the face of much criticism from customers.
Here’s an edited transcript of our conversation. For the full audio, listen to our podcast here.
Q: From the very first indication that there will be signs of a red flag warning or wildfire conditions, how are the wheels set in motion at SDG&E?
VANDERBURG: “... As we get closer and closer to the day on which we’re expecting Santa Ana winds, we are refining our forecast. We have our own weather models that we run here in-house that are basically designed specifically to forecast Santa Ana winds in our service territory. So we’re able to use that to start communicating how strong the winds might be, where they will be the strongest, so which circuits are going to experience the most adverse conditions. We also have various fire weather tools that look at the condition of the vegetation — the dead vegetation, the living vegetation, the grasses — and then starts to look at how that’s going to affect the fire environment when you combine it with the wind speed to understand where the fire danger is going to be greatest, how high is it going to be. We actually have models that take all this information and simulate tens of millions of wildfires every day across our service territory so we can get an idea of how they might spread in certain areas, what are we really looking at.”
Q: How do high winds exactly impact SDG&E’s ability to bring power to these communities?
VANDERBURG: “That’s a great question. So the biggest factor when it comes to the wind is flying debris. That could be from vegetation — from a palm frond or eucalyptus branch — especially in high winds, could break loose and fly a considerable distance and when it comes in contact with the power lines, it can cause power outages. Or you could have a very large tree that could be quite a distance from our power lines, but the winds could push that over and again, you could have contact there. Another issue is other kinds of flying debris like tarps or Mylar balloons. All sorts of interesting items can get picked up by the wind and come in contact with our power lines and cause outages. Another thing I think people need to understand about wind and power lines is, it’s easy to lose sight of the conditions beyond just your back yard. So we have areas in our service territory where these power lines run for many many miles across very different terrain and so there may be really strong winds occurring on one portion of a power line but that aren’t occurring in your neighborhood that are fed by the same power line. ...”
Q: Why are these planned outages happening this week? What were the big indicators that went into the decision making?
VANDERBURG: “First and foremost, they’re not planned. I think that might be a misconception. We have an idea. We know ahead of time which circuits are most at risk, but those decisions to shut off for safety are always made in real-time in our emergency operation center based on a multitude of factors. ... First and foremost it’s the weather conditions and the fire conditions. So, what are the wind speeds? How dry is it? What’s the fire danger like in that area? Is there a red flag warning? Another thing we’re looking at is, are there fires around the region, either in our service territory or outside of our service territory, that may be drawing resources away from our area? Another thing we look as is, if there were a fire to start in the area, could the aircraft get in the air and would it be effective in fighting that fire?
Another important one is observer reports. So we send crews, we send field observers out there to a lot of these areas who understand the system and are trained in this stuff that go out and they watch the power lines and they look at the vegetation and report back to our emergency operation center. So if they see something that’s a concern they will call us and let us know. … Reports from law enforcement or the public can cause a shut-off. If somebody calls SDG&E and says there’s a wire down, we may have to shut off in conditions such as we saw this morning before we can get somebody out there to investigate and in some cases it turns out that it may not be a power line. But when you’re dealing with 80 mph winds and single-digit humidity, you don’t have the luxury of waiting for someone to get out there and check it. That’s a sample of a lot of the factors.
Q: What goes into the communication process and working with the communities involved?
WINDSOR: “As the planning process is going on and our meteorologists are looking seven days in advance and as it’s getting closer to that event and the National Weather Service calls for a red flag warning, we proactively call customers who we believe could be impacted by that weather, whether it is a forced outage — meaning something happened to the system — or if it is a public safety power shut-off. So we’re notifying those customers, and we’re trying to do a large swath of people who really might be impacted, so it might be a couple thousand people, it might be 5,000 people, every situation, every event is different. So we are calling them possibly two days in advance, typically for sure sure a day in advance and we’re updating that information with the latest information that we have and then as the event progresses, if it is imminent that we’re going to do a power shut-off, then we notify them as well and we’ll continue to keep them updated through those phone calls, but we also use other tactics. … We feel that communication is critical and then once we do start doing those patrols of the power lines when it looks like we’re going to be able to safely restore power, we are, again, putting out another round of phone calls to be able to notify customers that we are doing that and then once it’s restored, we’re notifying them again. ...”
Q: How do you deal with frustration and feedback from people who have to go through this?
VANDERBURG: “One of the things we’ve done differently this year that’s new is after having gone to a lot of these communities over the past several months and talked to these folks and through town halls, is in listening to what they had to say, one of the things that they mentioned was a need for a resource center where they could charge devices and get information, maybe get some snacks. Just a place that they can go and have power to take care of some basic needs. So what we’ve done, in this case, is set up these community resource centers in these more rural areas and this is the first time we’ve ever activated them is in this event. … We’re going to continue to go out into the backcountry and continue to listen to folks and we’ll see what happens going forward in future years.”