The threat of fire continues to loom in various regions of Los Angeles that have faced devastating blazes for several days; however, there are indications that more favorable weather conditions over the weekend could aid firefighters in their battle against the flames.
Calm weather on Tuesday brought a momentary respite, allowing firefighters to make progress in extinguishing the fires. Nevertheless, a rare alert for a “Particularly Dangerous Situation” was issued for Wednesday in areas affected by the two fires, which have claimed at least 25 lives and razed thousands of homes. The National Weather Service has designated a red flag warning for the region stretching from the Central Coast down to the border with Mexico, valid from 3 a.m. to 3 p.m.
Forecasts indicate an improvement in conditions for firefighting may occur later in the week.
What conditions are optimal for firefighting? Just as factors like wind and drought propelled the rapid spread of the fires, the presence of calmer wind speeds, increased humidity, lower temperatures, and even wind or rain can significantly assist in extinguishing the flames.
Humidity in the atmosphere transfers moisture to the ground, trees, and other flammable materials. When these potential fuels retain more moisture, the risk of fire diminishes because they become less likely to ignite. Meteorologists pay close attention to relative humidity, which measures the amount of water vapor in the air. Fire warnings are typically issued when relative humidity falls to 15% or less, particularly in conjunction with heightened wind speeds.
A lack of strong winds is also pivotal for favorable fire control conditions. High winds can fuel the flames with oxygen and desiccate vegetation, making it more prone to catching fire. Though fires can persist even in the absence of wind, they do not spread as rapidly, which makes it easier for firefighters to contain them or for aerial firefighting efforts to be executed effectively.
Rain or snow can assist in extinguishing fires, although they often don’t provide a complete solution since moisture may evaporate quickly.
Will Los Angeles receive any relief? The forecast for Wednesday appears to predict worsening conditions, as low humidity coupled with vigorous Santa Ana winds challenges firefighting efforts. However, there are expectations of improvement later in the week.
Predictions indicate that by Friday and into the weekend, higher humidity levels and reduced wind speeds may arise, although little rainfall is expected. While precipitation can be beneficial, excessive rainfall could potentially lead to mudslides in already affected regions.
As conditions eventually ease, it’s important to recognize that climate change is contributing to the increasing frequency and severity of wildfires. Drought-like situations in the western United States are becoming more common, setting the stage for more extreme wildfire incidents in the future.
