Glass Fire burned 1 acre every 5 seconds in California. How fast can wildfires grow?

As the Glass Fire exploded overnight Sunday in California wine country, satellite images show that flames consumed 1 acre every 5 seconds, according to CNN.

Experts say extreme dry conditions in the West are fueling some of the fastest-moving wildfires ever recorded, with some so powerful they spawn their own weather systems.

“When you have a fire run 15 miles in one day, in one afternoon, there’s no model that can predict that,” said forester Steve Lohr of the U.S. Forest Service, the Associated Press reported. “The fires are behaving in such a way that we’ve not seen.”

The 36,000-acre Glass Fire threatens Santa Rosa and the Napa Valley, the California Department of Forestry and Fire Protection reported.

The wildfire, which began Sunday morning, has 0% containment, according to Cal Fire. Several Napa Valley wineries and resorts have been damaged or destroyed in the blaze.

The Glass Fire has destroyed 80 homes and forced tens of thousands of people to evacuate, including the entire town of Calistoga, The Sacramento Bee reported.

Winds topping 70 mph in some parts of California helped acceleratethe spread of the Glass Fire, The Sacramento Bee reported.

Wildfires normally travel up to 6 mph in forests and up to 14 mph in grasslands, Forbes reported. The flames speed up when going uphill.

“That fire last night was moving at about 40 mph because of the wind, down the hill into the city of Santa Rosa, and we’re hoping for better conditions here today,” state Sen. Mike McGuire told KTVU, according to USA Today.

The humidity factor

Experts say hot, dry conditions produced by climate change also are helping turn wildfires into infernos this fire season.

Jennifer Balch, a University of Colorado, Boulder, professor, says the air is sucking moisture from plant life at the highest rate in four decades, the Associated Press reported.

Those extreme conditions contributed to the fast spread of the Glass Fire overnight, said Craig Clements, director of the Wildfire Interdisciplinary Research Center at San Jose State University, according to The San Francisco Chronicle.

“A lot of times at night, the humidity drops drastically with dry air coming from the northeast, and that plays a role as well in fire behavior,” Clements said, the publication reported.

The higher the humidity, the better, experts say.

“Humidity recovery didn’t happen,” said Cal Fire spokeswoman Lynne Tolmachoff, The San Francisco Chronicle reported. “In the morning when you walk out, you see the dew on the grass or the car windshield. The humidity was too low for that to happen. Combined with dry fuels and an active breeze, it kept the fire active.”

‘Firenadoes’ during wildfires

In some cases, the dry tinder produces more heat energy, which super-heats the air and combines with smoke to create towering pyro-cumulus clouds that can produce lightning, thunder and high winds.

The extreme conditions also can create so-called “firenadoes,” which have been recorded at several California wildfires this season, McClatchy News reported.

“It’s really kind of a testament to the remarkable extremes that we’re seeing right now,” said Neil Lareau, a professor of atmospheric science at the University of Nevada, Reno, the Associated Press reported. “It really is kind of this vicious cycle that it gets into, and that’s when the fire really takes off and becomes these unstoppable infernos.”

This story was originally published September 29, 2020 at 10:39 AM with the headline "Glass Fire burned 1 acre every 5 seconds in California. How fast can wildfires grow?."