(CNN)Weather conditions in California for the next few days could be dangerous for fire activity, officials say, potentially making the state's wildfire season even more devastating.
And with a red-flag warning in effect for Northern California, fires in the region could present additional challenges for those on the front lines of the blazes as more than 41,000 people face evacuation orders.
"With extreme fire conditions and unsettled weather in the forecast, residents throughout northern California, including in the wider region around Lake Tahoe, are reminded to listen closely to local authorities and begin preparations to evacuate," Bryan May, public information officer for the California Governor's Office of Emergency Services, said in a video posted on Twitter.
The Caldor Fire, which has been burning east of Sacramento for 12 days, "could spread rapidly into more populated communities," May said.
If officials issue an evacuation warning, May added, then people should start preparing to leave and anticipate that an evacuation order will follow.
"And if you feel like you or anyone in your family may need extra time to get out, don't wait. Leave when an evacuation warning is issued. An evacuation order means there's immediate threat: Get out now," May said.
The red-flag warning issued Thursday by state agency Cal Fire will be in effect Friday morning through Saturday in anticipation of critical fire weather.
In the upcoming days, temperatures are expected to hit the high 90s, with winds moving at 10 to 20 mph and gusts between 25 and 35 mph, CNN meteorologist Gene Norman said.
Humidity is expected to be low, Cal Fire said, which increases the risk of fire activity.
A red-flag warning is issued when imminent weather conditions may result in extreme fire behavior that will occur within 24 hours. Those conditions include low relative humidity, strong winds, dry fuels and/or the possibility of dry lightning strikes, according to Cal Fire.
The Caldor Fire is the state's number one priority, Cal Fire said, as the fire has seared 143,951 acres and was 12% contained by Friday morning.
The fire's rapid growth has been so alarming that it prompted city officials in South Lake Tahoe to declare an emergency as winds pushed the blaze closer.