In such instances, the observer may see only a flash of light without hearing any thunder. Intra-cloud lightning most commonly occurs between the upper (or 'anvil') portion and lower reaches of a given thunderstorm. For example, there is intra-cloud lighting (IC), which takes place between electrically charged regions of a cloud cloud-to-cloud (CC) lighting, where it occurs between one functional thundercloud and another and cloud-to-ground (CG) lightning, which primarily originates in the thundercloud and terminates on an Earth surface (but may also occur in the reverse direction). Lightning can take one of three forms, which are defined by what is at the 'end' of the branch channel (i.e. Although lightning is always accompanied by the sound of thunder, distant lightning may be seen but be too far away for the thunder to be heard. This discharge allows charged regions in the atmosphere to temporarily equalize themselves, when they strike an object on the ground. Experiments have been conducted since the time of Benjamin Franklin however, we are still heavily reliant on theories as to how lighting behaves.īy definition, lightning is a sudden electrostatic discharge during an electrical storm. The Southland’s worst wildfires are driven by Santa Ana winds - and are almost always caused by people, downed power lines or equipment sparks.But despite all that human beings have learned over the centuries, a degree of mystery remains when it comes to lightning. Geological Survey, and research ecologist Alexandra Syphard analyzed California wildfire ignitions, they found that lightning was the cause of the majority of blazes in Northern California forests but accounted for less than a quarter of the starts in Southern California’s four national forests. When Jon Keeley, a scientist with the U.S. But they do occur in the mountains and deserts during the summer monsoon season.Ī recent lightning strike sparked the Dome fire, which incinerated stands of Joshua trees in the Mojave National Preserve. Lightning strikes are relatively rare in coastal Southern California. That is especially true after an exceptionally dry winter in Northern California, and a heat wave that has parched wildland vegetation. “It’s that they’re not producing enough rain to stop a fire from starting.” “It’s not that these storms aren’t raining,” Palmer said. The moisture in the storm systems is in the higher atmosphere, and much of it evaporates before it reaches Earth’s surface. Last weekend, Palmer said, lightning struck in one spot 10 miles from the nearest rainfall.

Two colliding weather systems - tropical moisture from the south and a high-pressure ridge from the east - are producing thunderstorms that spit out lightning but little rain. “I think people have short memories,” she said. In the span of a week, some of them have merged together to form the second- and third- largest wildfires in modern state history.īut big fires ignited by storms that streak the skies with thousands of lightning bolts are nothing new. This month’s explosion of lightning-sparked fires in the Bay Area will undoubtedly go down in the record books as the Siege of 2020. In 1999, hundreds of lightning-caused fires in the Big Sur region and the state’s north merged into two of the nation’s top blazes that year.ĭuring a 33-hour period in June of 2008, more than 5,000 lightning strikes ignited some 1,000 fires across Northern California, the Sierra Nevada and the Central Coast. It was the Siege of ’87, when two weeks of dry lightning strikes in late August and early September sparked thousands of wildfires in Northern California and Oregon, drawing an army of 19,000 firefighters. Federal officials described them as the “fires of hell,” a “holocaust” that blackened 775,000 acres of timber and chaparral and produced miles-high clouds resembling a nuclear bomb blast.

Heat lightning cause