Temperatures in the 100s and humidity in the teens have again multiplied the drought index into the danger zone.

Denton County commissioners declared not only a ban on outdoor burning, but also a local disaster. With the second action, Jody Gonzalez, as the county’s emergency management coordinator, can position crews and equipment in case a grassfire grows large.

“Yesterday (Monday), the humidity got down to 17 percent,” Gonzalez said. “At that point, it gets very dangerous, even with burn bans. A mechanical failure on a vehicle or a cigarette butt where it shouldn’t be is enough to start a grassfire.”

Violation of the burn ban is a Class C misdemeanor, punishable by a fine up to $500.

The disaster declaration also allows the county to seek reimbursement should a fire get large enough and expensive enough to fight that it qualifies for federal help.

Currently, county lands are averaging 593 on the Keetch-Byram Drought Index, which is used to assess the potential for fire. The highest possible reading on that index is 800, and a reading of 575 would be high enough to ban fireworks, Gonzalez said.

The southern, southeastern and central parts of the county are driest, according to data mapped by the Texas Forest Service.

There is only the slimmest chance for some relief from outer bands of rain from Hurricane Dolly, which is forecast to come ashore near Brownsville.

Instead, the hurricane could make the heat and high pressure worse, according to National Weather Service meteorologist Daniel Huckaby. Because a hurricane is a low-pressure system, air rushes in and rises up.

“And whatever goes up must come down,” Huckaby said, adding that the sinking air of a neighboring high-pressure system intensifies the heat. “We had a similar situation with Rita several years ago, where it got up to 105 to 110 degrees in Waco and Corsicana.”

With the long-range forecast continuing as mostly high heat and low humidity, Gonzalez said he was concerned the Keetch-Byram index would climb above 700.

“We haven’t been at 700 for quite some time,” he said.

PEGGY HEINKEL-WOLFE can be reached at 940-566-6881. Her e-mail address is pheinkel-wolfe@dentonrc.com .