A red flag warning issued for the eastern slope of the Sierra Nevada early next week could mean increased fire activity as major wildfires in northern California continue to burn.
The red flag warning, issued by the Reno office of the National Weather Service, is expected to cover the other side of the Sierra Nevada, from Mono County to the Oregon state border. Most of the warning covers the territory of western Nevada, including the town of Reno and surrounding areas, but South Lake Tahoe and other communities in the Tahoe Basin are included.
Scheduled to take effect at 11 a.m. Monday and through Tuesday at 5 a.m., Reno meteorologists are predicting rapid southwest winds with gusts of up to 40 mph.
Relatively low humidity levels are another cause for concern. The weather service said areas east of Highway 395 – which runs along the eastern edge of California and crosses Nevada via Reno – could see humidity levels between 15% and 20%.
The Reno weather office has warned that low humidity and gusty winds mean the fires could start and spread quickly before fire crews have a chance to contain them.
Fire cal responded to the red flag warning on social media by warning residents of affected areas to take special precautions outdoors in high fire danger.
The US Forest Service expects winds in the Caldor fire area to be between 30 and 40 mph. The fire, now largely contained but still very active, burned 221,774 acres. It is the 14th largest fire in California and is 76% contained.
“Fire operations are closely monitoring this weather front and its potential impact on the blaze,” the forest service said in an update Sunday morning.
On Saturday, some crews were diverted from the Caldor fire in order to fight a new blaze that broke out near the Ellicott Bridge over the Rubicon River. Nicknamed the Rubicon Fire, it was around 7 acres on Saturday afternoon. The forestry service said crews surrounded it and were working to clear it on Saturday night, but would need to be watched for several days to secure its edges.
Other areas on the western flank of the Caldor blaze remain active and many communities remain under evacuation order due to nearby fire activity, including some of the areas surrounding Lake Tahoe.
The Caldor fire began on August 14 just east of Omo Ranch and has since forced thousands of people to evacuate their homes in rural and forested areas of El Dorado County, as well as South Lake Tahoe. .
The Forest Service said 1,353 structures remain at risk from the fire, which destroyed 782 houses and damaged 81 additional structures. Much of the town of Grizzly Flats was destroyed by the mid-August fire.
A total of 1508 firefighters are assigned to the Caldor, with the help of 10 helicopters.
Although parts of the Dixie Fire’s eastern flank are included in the red flag warning, the crews have almost reached full containment.
With 963,276 acres and 94% containment, the Dixie Fire is the second largest wildland fire in the history of the state of California. Even though the massive fire hasn’t spread much in recent weeks, fire crews are still taking no risk in dangerous weather conditions.
“With low humidity, hot temperatures, dry fuels and gusty southwest winds, the recently fallen needle flow has the potential to reignite from the remaining hot spots inside the fire.” Forest Service officials said in an update Sunday morning. “Any spot outside the containment lines will have a high potential for substantial growth in fires today (which) could establish themselves and produce substantial growth.”
To prepare for the incoming winds, Forest Service officials said teams would patrol the lines and reinforce forces in the unconfined area to the far north of the blaze. The last remaining unconfined area is near Hat Creek Rim in the Lassen National Forest.
Crews expect peak winds to arrive on Monday, but will pass Tuesday as cooler and wetter weather is forecast for the area.
The Dixie fire has destroyed 1,329 structures to date and damaged 95 more. The wildfire destroyed most of Greenville in early August. The fire broke out on July 13.