Fire risks continue to be high in several parts of Los Angeles, which have been battling persistent wildfires for several days. However, there is optimism that improved weather conditions over the weekend may provide firefighters with the relief they have been awaiting.
Following some calmer weather earlier in the week, which assisted efforts to extinguish ongoing fires, a significant warning was issued for Wednesday. This “Particularly Dangerous Situation” warning pertains to a region affected by two fires that have resulted in at least 25 fatalities and have destroyed countless homes. The National Weather Service has issued a red flag warning for the area stretching from the Central Coast down to the border with Mexico, effective from 3 a.m. until 3 p.m.
Looking ahead, forecasts indicate that firefighting conditions should improve as the week progresses.
What constitutes the best conditions for firefighting? Similar to how wind and drought significantly contributed to the rapid spread of the flames, more favorable conditions for battling these fires include lower wind speeds, increased humidity, reduced temperatures, as well as any potential rain or snow.
The humidity level influences the moisture found in soil, trees, and other natural materials. When these combustible fuels have higher moisture content, the likelihood of a fire escalates diminishes, lowering fire danger. Meteorologists monitor relative humidity, which measures the amount of water vapor present in the air. Fire danger alerts typically arise when relative humidity drops to 15% or lower, particularly alongside elevated wind speeds.
Furthermore, calmer winds play a crucial role in creating better firefighting conditions. Strong winds can supply flames with additional oxygen and dry out vegetation, rendering it more flammable. While fires can persist without wind, they do not spread as rapidly, making it easier for firefighters to control them and for aerial firefighting units to launch from above.
Rain and snowfall can assist in extinguishing fires, although this moisture can evaporate rather quickly, often not providing complete relief.
When can Los Angeles expect relief? The Santa Ana winds are anticipated to continue through Wednesday but are set to diminish by evening. According to meteorologist Mike Wofford from the National Weather Service, winds over the Palisades fire area are present but less intense than before.
On Thursday, the usual sea breeze is expected to return, facilitating the influx of moisture from the Pacific Ocean into the region, thereby increasing humidity levels which should prove beneficial for firefighting efforts. This onshore breeze is likely to persist throughout the weekend.
While rain is not anticipated in the immediate future, Wofford notes that any heavy rainfall could raise the risk of mudslides, especially in areas already affected by fires. Another round of Santa Ana winds is expected early in the upcoming week, although it is too soon to predict its intensity. Current forecasts suggest wind gusts may peak at around 40 miles per hour or less, which are considered manageable.
In the aftermath of these fires, experts warn that climate change is likely to contribute to increasingly frequent and severe wildfires in the future, with prolonged drought conditions expected in the western United States.
As firefighters make progress against a blaze, they share information regarding containment levels. Fire containment refers to the creation of fire lines around sections of the blaze, often established through dirt trails cut by shovels or bulldozers, which help prevent flames from spreading further into grass or trees. For instance, a fire is cited as being 25% contained when the perimeter of a quarter of the fire’s edge is secured.
A fire is deemed controlled when it is fully contained, with all flames and smoldering materials extinguished, and any unburned fuels within approximately 300 feet of the fire line removed. The fire is classified as fully extinguished when there are no detectable hot spots or smoke within the containment lines for a minimum of 48 hours.
Firefighting teams often remain on-site for several days or even weeks to ensure thorough clean-up of burned areas. They may cut down unstable trees, eliminate brush and potential fuels that could rekindle fires, clear roadways, and conduct other necessary activities to guarantee safety in the area.
