WEAVERVILLE (CBS/AP) — Fire officials say a lightning-sparked fire in the Shasta-Trinity National Forest is growing extremely slowly, allowing crews to gently back it down toward containment lines.

Fire spokesman Corey Wilford said the fire was 45 percent contained as of Monday morning. It only grew 19 acres overnight to a little over 1,500 acres.

READ MORE: Despite Fines, Pleasant Hill In-N-Out Remains Defiant Over Customer Vaccine Verifications

The fire broke out in the forest about halfway between Eureka and Redding on Tuesday. Crews battling it have experienced 99-degree heat, but were expecting cooler temperatures this week.

READ MORE: Mariposa Sheriff To Announce What Killed Family On Hike In Sierra National Forest

An evacuation order for about 100 people along a county road southeast of the fire was lifted Sunday, though those residents and about 240 people in the town of Hyampom were told to be ready to leave if there are flare-ups.

MORE NEWS: UPDATE: Judge Denies Bail for Los Gatos Mom Accused of Hosting Drunken Teen Sex Parties

© Copyright 2015 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.