Red flag warnings in 8 states, when millions are exposed, increased the risk of forest fires

The National Weather Service released red flag warnings in eight states on Tuesday, which means that tens of millions of Americans are currently an increased risk of forest fires due to the combination of strong wind and unusually dry conditions.

In Texas, Oklahoma, Kansas, Missouri, Colorado and the parts of Arizona, New Mexico and Nebraska, low humidity and winds are expected over 25 miles per hour with a height of up to 65 miles per hour.

On Friday, similar conditions led to more than 130 fires in Oklahoma, the State Ministry of Health said that they killed at least four people, injured 200 more and destroyed over 400 houses.

When are red flag warnings output?

The National Weather Service “Warnings of the Red Flag on” Warning Fire Manager in Bundeslanden on conditions that are very unfavorable for prescribed burns, “says the agency on its website.

This provision is based on three factors: “How much water is kept by small vegetation such as grass, leaves and mulch, which only take about ten hours to react to changes in the dry/wet conditions”, relative humidity values ​​of less than 25% for several hours, and wind speeds of “at least 15 miles per hour” for several hours, “states the NWS.

These conditions, which dramatically increase the risk of forest fires, typically occur in autumn and spring. But the fatal fires, which devastated a large part of the Los Angeles area in January, show that they can also appear at other times.

The conditions that are experienced in the warnings of the red flags do not guarantee that a running fire will occur, but they make them much more likely. A study by the World Weather Attribution, a consortium of climate scientists, showed that “from 2006 to 2020 8% of the forest fires in the western USA and 19% of the large forest fires” took place on days when a warning was issued for red flags.

Not just a western problem

As in the past year, the conditions for red flags are not just a problem for western countries. In most cases they were released in South Florida on Monday. At the beginning of this month they went to the Carolinas. In October in New York, Connecticut and New Jersey, where forest fires threatened hundreds of houses.

“In response to the drought in combination with other local factors (heat, low humidity, strong winds), the National Weather Services Offices all over the northeast published an unusually high number of red flag warnings for the previous month,” says a message that was published on his website on November 21, 2024.

The ongoing drought conditions in New Jersey have led to a previous increase of 266% in the number of forest fires in the course of the previous year, Gothamist reported this week.

“Indeed, we had a drier winter season that has held incredibly dry late summer and autumn,” said Shawn Latourette, Department of Environmental Protection Commissioner, during a media meeting last week.

The link of climate change

Numerous studies have shown that rising global temperatures increase the length and intensity of the forest fire season.

“Climate change, including increased heat, extended drought and a thirsty atmosphere, has been an important driver in the past two decades to increase the risk and the extent of the forest fires in the western United States,” explains NOAA on its website.

We also know that the evaporation rates have increased dramatically in the further course of the temperatures, which makes vegetation like grasses and leaves much more susceptible to burn.

To what extent climate change affects the wind speeds is still a question of the debate, but a study from 2019 showed that the wind speeds have increased in Europe, North America and Asia since 2010.