Play Live Radio
Next Up:
Available On Air Stations
Watch Live

KPBS Midday Edition

Tracking Santa Ana Winds During San Diego's Wildfires

Tracking Santa Ana Winds During San Diego's Wildfires
Tracking Santa Ana Winds During San Diego's Wildfires
GUESTS:Steve Vanderburg, Senior Meteorologist, SDG&E Weather Network Brian D'Agostino, Senior Meteorologist, SDG&E Weather Network

MAUREEN CAVANAUGH: This is KPBS Midday Edition, I am Maureen Cavanaugh. Our top story on Midday Edition, San Diegans are taking stock of the damage caused by last week's wind driven wildfires. In all, the multiple fires scorched 27,000 acres and destroyed more than sixty structures and apparently resulted in one fatality. We will talk later in the show about what it takes to recover and rebuild from a fire, but first we will explore an innovative weather sensor networking San Diego County that is dividing cutting edge information to both San Diego Gas and Electric and firefighters. State regulators blamed poorly maintained power lines in San Diego's backcountry for sparking the deadly 2007 wildfires. Since that time the esteemed SDG & E has developed the new weather sensor program. Joining me are two senior meteorologist from that program, Steve Vanderburg and Brian D'Agostino, welcome. Thank you both for coming in. What was last week like for you? STEVE VANDERBURG: It was a bit unusual in that we had significant Santa Ana winds in combination with drought conditions leading to the potential for large fires in May would normally be expected green layer, clouds, and cool temperatures. Obviously it was a very busy week for us, as we were providing weather intel to the companies in order to ensure we were operating safely. MAUREEN CAVANAUGH: Brian, where you actually in the backcountry? Had use secure the data that you used? BRIAN D'AGOSTINO: We are actually at an operation center here in San Diego. Last week really gave us the opportunity to put into action everything that we have been preparing for. Getting all of that information from the weather network that we have out there, and integrating it into our operations and trying to really guide our crews and make really good decisions from that information. MAUREEN CAVANAUGH: What is the weather sensor network actually like work with you have monitor setup, what gives you the information? BRIAN D'AGOSTINO: One thing that is so unique about this network is the size of that, we of 149 stations across the backcountry. The majority of it is east of the fifteen freeway, but now we have sensors going along the coast as well. We have to monitor weather conditions west of the mountains. That is where the majority of the stations are located. MAUREEN CAVANAUGH: What do they look like? BRIAN D'AGOSTINO: On our power poles we have a 15 foot cross arm which comes out about 20 feet above the ground and out there we have the winds sensor and we also monitor humidity, temperature, and in some cases we monitor solar radiation. MAUREEN CAVANAUGH: Steve, you previously worked with the national weather service, how is this information different from what the National Weather Service can provide? STEVE VANDERBURG: First it gives us the granularity that we need to see what is actually happening out there. Prior to the installation of the weather network there were very few observations in the backcountry. It was unknown as to how strong winds were and when the strongest winds were occurring. This gives us the situational awareness we never had before. MAUREEN CAVANAUGH: How many sensors are out there? STEVE VANDERBURG: We are to 149 weather stations and we have another dozen or so coming this year. MAUREEN CAVANAUGH: The utility companies protocol of shutting down power to areas where fire conditions are dangerous has been controversial. Here is what a critic, Dianne Jacob of the County Board of Supervisors told us last week about the policy. [AUDIO FILE PLAYING] JACOB: My caution and what I indicated to SDG & E, and it is not the first time, whenever any proactive shut off is done that could pose a risk of property to those people who depend on groundwater. They rely on electricity to pull the water out of the ground which enables not only property owners to access water during the fire but also to firefighters as well. The risk is, if there is a proactive shut off without eminent public threat to public safety, they are risking life and property by doing that. [END AUDIO FILE] MAUREEN CAVANAUGH: That was Dianne Jacob of the San Diego County Board of Supervisors, Steve what criteria does SDG & E used to make the decision to shut down power to a certain area? STEVE VANDERBURG: There are a lot of factors that go into this. One is the weather conditions occurring right now in the backcountry on various circuits. Also the fire danger, what is vegetation like? Is the vegetation conducive for large fire and rapid fire growth? Also we send people to the field ahead of time before the winds develop ahead of time to the highest risk areas and we get observations ahead of time. Do we see debris flying through the air? Is there movement on the conductors? Is there anything we should be aware of that is an imminent threat to the system? It is a last resort we take. There are a lot of factors we take into this. MAUREEN CAVANAUGH: Imminent, Dianne Jacob use that when she said she wanted to make sure these will active shutdowns are for imminent danger. Brian, is there a calculation you use to provide whether it is an imminent danger, or if it is just your best call considering a lot of factors? BRIAN D'AGOSTINO: It is a culmination of subject expertise that we have there. Like Steve said, trained electricians in the field whose jobs are to monitor the system and keep it safe. They keep a very close eye on it and if they call into operations and say this is very unsafe, then actions are taken. In the event that we had last week we saw wind gusts over 85 miles an hour on portions of our system and other areas that are not prone to extremely strong winds often. We have seen hurricane force wind gusts and that creates an unsafe situation. MAUREEN CAVANAUGH: You also provide information to firefighters during wildfires, is that right? BRIAN D'AGOSTINO: That is correct and that is another great point about the SDG & E weather network, all of this information is not only over to the National Weather Service service to support their forecast, but the company has gone as far as creating handheld web apps to deliver all of this information to firefighters so that they have all of the latest information out in the field, while are they are trying to fight these fires. MAUREEN CAVANAUGH: Steve, one of the things that you guys are developing as you study Santa Ana winds is you are trying to create a method of rating wind events like the categories we heard for hurricanes or tornadoes. How are you going about doing that? STEVE VANDERBURG: This involves a collaboration with the US for service with the National Weather Service with UCLA and others work basically it takes all of the data we have collected and tries to figure out where the correlation is between the strength of sin and as, condition of vegetation and fire risk and once we have all of this information which we do now, we are able to go into every event and know where we stand in terms of fire potential, and how this ranks historically. This is going to be a product that will be available to the public in fall, by the end of the summer and beginning of fall. BRIAN D'AGOSTINO: That is something we're really looking forward in moving forward and releasing to the public in the upcoming fall in October or November. It is not just SDG & E product like any stretch. It is really a collaboration between the for service and the weather service and UCLA, and this partnership. It is a good example of cutting edge science really starting to push forward in terms of understanding of wildfire potential. STEVE VANDERBURG: One of the exciting things about this product is that it lays out simple steps that people can take to prepare for an event. With this information it helps you prepare for an event, charge your cell phone, make sure your vehicle has a full tank of gas, that kind of thing. MAUREEN CAVANAUGH: Let's say that your forecast is for a category four wind event, that would be very convenient, I imagine, for people. Because there would be protocol attached to that. Agencies could do certain things, the general public would do certain things, it seems sort of odd considering how long Santa Ana's have been around that nothing like this has been about developed so far. That must be the intention of getting this up and running, so everyone knows where we are at a certain time and what we need to do. BRIAN D'AGOSTINO: And it creates a uniform understanding of the fire potential, as we come into an event. It's important, we are all able to understand the potential and communicate one message. MAUREEN CAVANAUGH: What are the challenges of tracking Santa Ana winds? STEVE VANDERBURG: With Santa Ana winds you can get a wide variety of wind speeds in a very short distance, so one of the challenges that we face is how will the wind very from this point to that point every hour, that is a very difficult challenge. The other challenge is how far down the mountain are the winds going to make it? Sometimes they are confined just to backcountry. Sometimes they reach all the way to the coast. Those are challenges we have been working on the last several years. I think we have made pretty good progress in figuring out the Santa Ana wind puzzle and how to forecast these better. MAUREEN CAVANAUGH: Brian, one of the things that you had found out in this research is that for a long time they thought that Santa Ana winds were strongest in alleys and canyons but actually now the idea is that winds are strong this on mountain slopes, is that right? BRIAN D'AGOSTINO: That is correct and the way that we described it is analogous to a rapid and the river. If you see a river flowing and it hits a rock the water quickly goes down the back slope of the rock and that is very similar to what we're seeing in a Santa Ana winds. Understanding this has enabled us to go in and focus on some of those areas during the strongest events. Not only in real-time, but we also have the ability to strengthen the system, hardened the electric grid and focus accurate efforts to make sure these areas experiencing the strongest winds are the areas where we are making sure that the system is able to withstand it. MAUREEN CAVANAUGH: One of the things that the national media especially was fascinated about during the wildfires were the fire whirlwinds, they called them ìfirenados.îThat developed during our fires last week, is this a new phenomenon? STEVE VANDERBURG: It is not a new phenomenon, is an indication of extreme fire behavior. So, when you get very intense fires burning and drive education, you can get all sorts of interesting fire behavior, like firewhirls. MAUREEN CAVANAUGH: Is that because of the intense heat? STEVE VANDERBURG: It is a combination of intense heat and updraft, so all of this heat is rushing towards the fire and upward, this causes the spin to intensify and results in what looks like a fire tornado. MAUREEN CAVANAUGH: They don't move, do they? STEVE VANDERBURG: They move locally, you won't see one that will move a quarter-mile. In a sense, they are confined to that spot. They can pop up anywhere along the fireline, particularly when you have these extreme weather conditions. MAUREEN CAVANAUGH: Part of the weather sensor network is to establish more information about San Diego's microclimates, Brian can you give us an example of how establishing a microclimates might help firefighters during a wildfire? BRIAN D'AGOSTINO: Absolutely, this brings us straight to safety concerns that we see. Like Steve mentioned, you can go a quarter mile in either direction during the Santa Ana as an winds can be twice, even three times as strong. Being able to identify if the fire is moving into a very high wind quarter, that is very important information to know not only for fire agencies and first responders but also for SDG & E crews trying to make it safe, gas crews making sure that we are getting gas turned off, monitoring the electric system and all of that, it is very important information to have an that is one example of how understanding microclimates can increase safety. MAUREEN CAVANAUGH: Sometimes when we are watching firefighters attack a fire either on the scene or on television and we are wondering why don't they go in that direction because that is where the higher seems to be headed, or why don't they stand their ground right here? Some of those decisions might be made by a better understanding of the climate areas that they are in then perhaps the general public has, is that right? STEVE VANDERBURG: Yes, certainly you will not want to attack the head of a fire in fifty mile-per-hour winds. When we talk to firefighters out there who have been doing it their entire careers, they understand where these areas are and with our weather network on top of that we are finding new ones all of the time. This sort of collective understanding of where the weather is most extreme, obviously you're going to want to be more cautious on how you are attacking the fire in these areas. MAUREEN CAVANAUGH: Is there anything that you would like people in San Diego to know about Santa Ana's and fires that is perhaps not always remembered or understood here in San Diego? 23 the first thing that comes to my mind, through these events are begin to appreciate the firefighting capabilities we have in San Diego. Being able to provide this information, is an honor to provide support to these firefighters whenever we can. I will try to transition to Steve as well, preparedness from the San Diego County office of emergency management. STEVE VANDERBURG: I think as we have seen technology improve and the science of fire weather improved and now with applications being available to the public, I think there is a lot of information out there that is available that we did not necessarily have in 2003 or 2007. For instance, we had been using that San Diego County emergency application, SD Emergency which has been a fantastic resource. It gives you a wacky relation information, perimeters on fires and gives you tips on how to prevent prepare for such event. There is a lot more information out then there ever was in the past that is very useful as we just experienced. MAUREEN CAVANAUGH: And quickly, I know that you're not necessarily a forecaster, but do we have any other Santa Ana Events in the next couple of weeks that you're seeing? STEVE VANDERBURG: Right now it seems like we're going to see a return, or I could say an arrival of the typical May gray weather pattern. Cool with morning low clouds, afternoon sun, the opposite of what we have just experienced. MAUREEN CAVANAUGH: A nice break. Thank you both, Steve Vanderburg and Brian D'Agostino both senior meteorologists with SDG & E Weather Network.

A weather sensor network in San Diego County is working to aid the fight against wildfires.

The network pulls information from 149 weather stations across the county every 10 minutes, including data on temperature, humidity and wind speed, said Steve Vanderburg, a senior meteorologist with the SDG&E Weather Network. They also plan to add 12 more stations by next fall.

"We go so far as developing a web application that brings all of this information in real time to firefighters in the field," said Brian D'Agostino, a senior meteorologist with the SDG&E Weather Network. "


The Santa Ana winds that were at least partially responsible for last week's fires are very difficult to track, D'Agostino said. That's because the San Diego region has lots of different microclimates.

"In some areas just a quarter-mile away from each other might see winds with a 30 to 40 mph difference," he said. "What we do is take all this information, and by giving it into our operations, we're able to put our crews in the areas with the strongest winds."

State regulators blamed poorly-maintained SDG&E power lines in San Diego's back country for sparking the devastating 2007 wildfires. Since that time, SDG&E developed this tool.

Vanderburg said decisions to cut power several times during last week's fires were based on many factors in addition to winds.

"One is what are the weather conditions like right now in the backcountry on our various circuits," he said. "But two, what's the fire danger, what's the vegetation like. Is the vegetation conducive for large fire and rapid fire growth. Also, we send people out into the field ahead of time, before the winds even develop, to these areas that we pinpoint as the highest risk areas. We then get their observations in real time."

Corrected: November 28, 2023 at 10:21 PM PST
Brendan Price and Claire Trageser contributed to this story.
KPBS has created a public safety coverage policy to guide decisions on what stories we prioritize, as well as whose narratives we need to include to tell complete stories that best serve our audiences. This policy was shaped through months of training with the Poynter Institute and feedback from the community. You can read the full policy here.