California’s deadly wildfires

The Woolsey Fire seen from Topanga, California (Photo courtesy of Peter Buschmann, Forest Service, USDA).

By UM News

The Woolsey Fire seen from Topanga, California (Photo courtesy of Peter Buschmann, Forest Service, USDA).

California’s deadly wildfires

By UM News
UM atmospheric scientist Paquita Zuidema answers critical questions about the California wildfires.

The California wildfires have taken an unprecedented toll, claiming more than 80 lives, destroying thousands of homes, and laying waste to a total area of nearly 400 square miles. Hundreds of people are still missing.

But why is Southern California such a tinderbox, and how is smoke from the massive fires affecting the atmosphere and weather in that part of the country?

Paquita Zuidema, an atmospheric scientist at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and the co-leader of a NASA study investigating how smoke generated by agricultural fires in Africa affects regional and global climate, answers some of the most critical questions about the California wildfires.

Why does California have so many wildfires?

To some extent, this reflects wildfire suppression practices of the past. A difference from the fires and burning practices in Africa that I have been studying is that the systematic practice of setting small fires every year to clear the agricultural fields has the side benefit that fire suppression has not allowed large quantities of biomass to grow, reducing the risk of the large fires California and the West are now contending with. In the West, climate warming combined with the plentitude of biomass has encouraged the pine bark beetle, and currently there are large stands of dead trees dotting the West. In California this fall, the atmospheric humidity levels have been particularly low, setting the stage for the current fires.

What kind of impact can smoke from the California wildfires have on the atmosphere and regional weather patterns?

Smoke consists of fine particles that can easily enter people’s lungs, so there is a clear connection with human health and air quality. The reduction of sunlight reaching the ground will reduce the land heating during the daytime, which in turn reduces the likelihood of afternoon thunderstorms that can help clear out the smoke.

Could climate change be making the California wildfires worse?

Yes. The West is becoming warmer, facilitating the conditions in which the pine bark beetle can foster, and helping to dry out the woods. Climate change makes the forests more susceptible to fires.

Smoke from the California wildfires has reached the East Coast. How can smoke travel that far?

The jet stream, a zone of strong winds in the mid-latitudes, travels from west to east, and can easily transport the smoke for thousands of miles.


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