In recent weeks, California firefighters are continuing to struggle with containing a blaze that is ripping apart nearly 9,300 acres of land near Yosemite National Park in the Sierra Nevada Mountains. While this is a frightening event, unfortunately it’s a normal occurrence and harsh reality for many people living in the western part of the United States. Many people may feel powerless and unsure of how they can help. It is crucial to know what causes these wildfires and how citizens can protect themselves, their families, as well as their property.
The biggest initiator of wildfires is due to human activity. It has been stated by the National Park Service that as many as ninety percent of wildfires are caused by campfires being left unattended, the burning of debris or leaves, negligently discarded cigarettes, and intentional acts of arson. Fortunately, in some states, legislation has been passed to prohibit acts of burning leaves on property, as well as the time of year of doing so. In Massachusetts, for example, the timeframe of burning leaves is from January 1st to May 1st and only from 10:00 AM and 4:00 PM. It also must be at least 75 feet from buildings. However, even though this law is enacted, there are still twenty-two areas in Massachusetts that prohibit the act of burning leaves completely.
Another cause of wildfires is due to lightning. Lightning is described as having two components - dart leaders and return strokes. The leader is the build-up of positive charges on the ground beneath the cloud, attracted to the negative charge in the bottom of the clouds. The return streaks of light are a series of strokes that produce the actual lightning bolt or flash that we see. There are two types of lightning which are described as “cold lightning” and “hot lightning”. Cold lightning is a return stroke with intense electrical current but of relatively short duration. Hot lightning has currents with less voltage, but these occur for a longer period of time. Fires are usually started by unusually long-lasting hot lightning bolts. Wind is also impactful on creating wildfires. For example, in California there is a phenomenon known as the Santa Ana winds. These winds are strong, extremely dry down-slope winds that originate inland and affect coastal Southern California and northern Baja California. They originate from cool, dry high-pressure air masses in the Great Basin. Santa Ana winds are known for the hot, dry weather that they bring in autumn but can also arise at other times of the year. They often bring the lowest relative humidity of the year to coastal Southern California. This low humidity, combined with the warm, heated air mass, plus high wind speeds, create critical fire weather conditions. Also known as "devil winds", the Santa Anas are infamous for fanning regional wildfires.
Homeowners in wildfire prone areas should keep all of this information in mind, as well as taking their steps to prevent the spreading of these fires. First off, homeowners should remove combustibles including firewood, yard waste, barbecue grills, and fuel cans from their property. Before evacuating, close all windows, vents, and doors to prevent a draft. Shut off natural gas, propane, or fuel oil supplies as well as filling any large containers (such as pools, hot tubs, garbage cans, or tubs) with water to slow or discourage fire. Homeowners should heave warning from local first responders, police and/or firemen for when to evacuate. You should never stay and try to put out the flames yourself, as the flames can engulf properties in mere minutes. While fire season is a scary event for anybody - people that live in wildfire prone areas should be knowledgeable on what to do, try to remain calm if they are asked to evacuate as well as to be safe at all times.
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©2018 Weather Forecaster Michael Ames