Red Flag Warnings up for the Bay Area and Sacramento Valley

Residents and businesses prepare for gusty winds and low humidity, the recipe for wildfires

With the Caldor Fire still raging near Tahoe already having scorched 221,775 acres and the KNP Complex Fire threatening the treasured Sequoias in the Sequoia and Kings Canyon National Parks, California is again in critical fire danger.  The National Weather Service has issued a Red Flag Warning until Tuesday evening for a large Northern and Central California area from Redding to Sonoma to the Santa Cruz Mountains, including parts of the Los Padres National Forest and west to the West Sierra Foothills. This encompasses Sacramento, Stockton, Modesto, Oakland, and Napa.

According to the National Weather Service, a Red Flag Warning means fire weather conditions are occurring now or shortly.

"A combination of strong winds, low relative humidity, and warm temperatures can contribute to extreme and erratic fire behavior," the NWS stated. 

Weather Specifics

A strong, low pressure area will dig across the Pacific Northwest into the Great Basin tonight, which will turn the normal Westerly winds north and offshore tonight. Then, as the system strengthens will shift, increasing winds Northwest.  The North and Northwest offshore winds are very dry as they travel over the land instead of the more humid Westerly winds off the Pacific.

Gusty Northeast winds will pick up late tonight and peak Monday.  North winds 30-50 mph and gusting higher paired with 8 - 15% relative humidity (recovering overnight only 25-50%) create optimal conditions to set the very dry landscape on fire with any spark.  Embers travel on the 50 mph winds spreading the fire quickly.  Higher elevations and mountain passes will experience the strongest winds.  Some of the most favorable peaks will see winds blowing 60-70 mph.

Areas to Watch

Areas to watch include the East Bay Hills and Valleys, the residents of which just marked the 30th anniversary of the deadly Oakland Hills Firestorm, which raged through the Oakland suburbs, killing 25 people. North Bay mountains, home to California’s most expensive Cabernet vineyards, are prepping for the possibility of fire and days with no public power. Public Gas and Electric has already warned tens of thousands of residents and business they will shut the power down if winds hit a critical point through Tuesday. 

Vintner Jennifer Lamb has her two generators ready to take over the irrigation in such an event. She is nurturing brand new vines after losing her award-winning Cabernet vineyard at Herb Lamb Vineyards to the Glass Fire in September 2020.

"I’m on Howell Mountain, so we just get more wind.  It’s hard farming when you have no access and no power.  They close all roads and only allow emergency vehicles," Lamb said. 

In 2020, she had her generators installed just three days before the Glass Fire started.  Other wineries trust generators to run fermenting and wine tanks during these critical weeks of winemaking after just harvesting the fruit.

"One silver lining to the Glass Fire," Lamb says, "Getting an Ag Pass is now so much easier and online."

One needs a Napa County Agricultural Pass to access their properties and businesses in fire areas behind fire road closures.