News In Numbers: Half Of San Diego County Extremely Vulnerable To Wildfire
August 29, 2016 1:19 p.m.
Wildfire Predictions For San Diego County
Tom Rolinski, meteorologist, U.S. Forest Service
San Diegans have a visual resource to determine the most hazardous wildfire areas in the county using a national map compiled by the US forest service, KPBS news partner inewssource has put up a map. According to Ingrid Lobet, that image is a stark reminder of San Diego's vulnerability to fire.
Almost a quarter appears red in an interactive map, meaning it has high potential to burn even for those who are quite a rare, this map is sobering. The red zones including the areas West of Interstate 15. The lands of the Sycuan Band of the Kumeyaay Nation, Los Penasquitos Canyon Reserve, lower Otay Mesa. Much of the art between fall back -- Fallbrook. 20% of land is not quite as I but still high potential. You can see the map at. You can see the email@example.com I'm Ingrid Lobet.
Joining me is Tom Rolinski. How badly is California's drought affecting wildfire risk in San Diego County?
Currently, much of southern and central California are in a severe drought. This has been ongoing for five years across the region. That's stressing our vegetation to the point where we are seeing a lot of our vegetation historically dry levels. Normally, our moisture is lowest around late September into October. We are seeing levels now, of our moisture that is lower than that.
The fire service does breakdowns of fire risk in various time frames. What is San Diego counties potential for the next week?
For the next couple of days it will be hot and dry. That will elevate our fire potential locally for the next couple of days. Beyond that, we will see cooler weather, deeper Marine layer on the coast and it will be more in some -- influential during that time. Our fire potential is likely to lower, as we get into the middle to latter part of the work week.
What about looking out, if you can for the next few months for the fall season?
As we get into the fall season, we start to see our Santa Anna winds return, combine that with dry fuels. That will create the potential for significant fire activity. That depends on if we get ignition's. If we don't get ignition's, we won't have fire activity. The potential will be there, due to again the extremely dry fuels and the potential for Santa Anna winds returning.
What information do you use to determine the wildfire risk during a certain time frame? We have the ongoing drought, what other factors have to be there for the fire risk to go up expect the forest service --
We use fuel moisture measures, the different types of fuels, there are different types of moisture that we record in those different fuels. We basically, get an assessment of fuel conditions across the region, we combine that with the long-term projections and whether, so we are looking at temperatures, the potential for windy periods in the next month or three months and we combine that information to produce fire potential product. Taking a look at what the fuels are doing and what the projected weather will be, we can get a good idea of how are fire will shape up.
Sometimes, it seems meteorological he we cannot win in Southern California. When it rains it spurs growth, which is fuel for wildfire and if it's dry, what growth there is turns to tinder. Is there any scenario that makes us safer against fire?
There are situations, where it's been so dry we have not had vegetation to burn. In those situations, sometimes we can have fewer fires just because there is less light vegetation around. If we don't have annual grass that develops during the spring and early summer, that tends to mitigate some of our fire activity. The other situation that can develop is giving us a lesser potential for fire, if it is a wet winter and it stays cool throughout the summer, that's happened a few years, it's not very often. Those years tend to have fewer wildfires with those conditions.
As you have said, if we have no ignition -- ignition source.
It's all dependent on ignitions, whether it's human are lightning. When we talk about potential it's a probability that is based upon getting in ignition. That is hard to determine, whether our forecast are accurate because it's hard to measure potential. If we don't have an ignition, that potential can still be there but we would not get a fire. Even though we may have a high potential for significant fire activity, it doesn't mean that potential for fire is not there.
Still ahead, notes from the battle on the home front. During the last 15 years of war. You are listening to KPBS Midday Edition