More than half of the lightning strikes in northern California over the past three decades have taken place on days with little to no rain, sparking some of the most destructive fires in the state's history.
James Dinneen is a writer.
There is a fire in the national forest.
The AP/Shutterstock is owned by Noah Berger.
Almost half of the lightning strikes in central and northern California occurred on days with very little rain. Three of the most destructive fires in California history were caused by dry lightning.
A normal dry thunderstorm develops with a warm updraft carrying water to higher altitudes where it forms clouds and lightning. If the thunderclouds form on top of the hot, dry air, rain won't fall. The atmosphere needs to be hotter, drier, and lower. There is no rain in the area to put out any fires caused by dry lightning.
More than 5000 fires have been started by lightning in California since 1987 and Kalashnikov and his colleagues looked at the meteorological conditions behind it.
The researchers used records of lightning strikes and precipitation in the region which included the fire-prone central and north coast and the forested Sierra Nevada. The strikes were recorded by a network of ground-based sensors.
The locations of dry lightning strikes and the meteorological conditions on days with dry lightning were looked at. Between July and August, dry lighting occurred most often, though it was most widespread in the summer months. According to Kalashnikov, dry lightning occurred as late as October.
Mike Flannigan says that the more detailed view of the meteorology behind dry lightning in California could help create early warnings. Australia, Siberia and Canada are places where dry lightning is a growing risk.
Climate change is leading to more severe and frequent fires as well as more frequent lightning.
The majority of fires in the US are started by people. In remote places where it takes longer for anyone to notice the fire, lightning clusters can ignite many points at once.
Thousands of fires were started by dry lightning in California during the "Fire Siege of 1987", burning more than half a million acres. The fires burned 2.5 million acres.
The journal title is Environmental Research: Climate.
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